Irregular plurals word list

Updated on November 04, 2019

Most English nouns form their plural by adding either -s (books, bands, bells) or -es (boxes, bunches, batches). These plural forms are said to follow a regular pattern.

Irregular Plural Nouns

«The Penguin Writer’s Manual»

«There are no easy rules, unfortunately, for irregular plurals in English. They simply have to be learnt and remembered.»

Not all nouns conform to the standard pattern. In fact, some of the most common English nouns have irregular plural forms, such as woman/women and child/children. In addition, several nouns have alternative plurals, one regular and the other irregular.

In regard to these alternative forms, there are no strict rules to guide our use of them.

«The Cambridge Encyclopedia of the English Language»

«People have to learn which form to use as they meet the words for the first time, and must become aware of variations in usage. When there is a choice, the classical [irregular] plural is usually the more technical, learned, or formal, as in the case of formulas vs. formulae or curriculums vs. curricula. Sometimes, alternative plurals have even developed different senses, as in the cases of (spirit) mediums vs. (mass) media, or appendixes (in bodies or books) vs. appendices (only in books).»

As you’ll see in the list that follows, many words with irregular plurals are loanwords that have kept their foreign plural forms (or at least held on to those forms as alternatives to regular English plurals).

100 Irregular Plural Nouns List

In the list below, you’ll find singular noun forms in the left column and the corresponding plural forms in the right column. When a noun has more than one plural form, the irregular one appears first, though that doesn’t necessarily mean that the irregular form is more widely accepted than the regular form.

addendum	addenda or addendums
aircraft	aircraft
alumna	alumnae
alumnus	alumni
analysis	analyses
antenna	antennae or antennas
antithesis	antitheses
apex	apices or apexes
appendix	appendices or appendixes
axis	axes
bacillus	bacilli
bacterium	bacteria
basis	bases
beau	beaux or beaus
bison	bison
bureau	bureaux or bureaus
cactus	cacti or cactus or cactuses
château	châteaux or châteaus
child	children
codex	codices
concerto	concerti or concertos
corpus	corpora
crisis	crises
criterion	criteria or criterions
curriculum	curricula or curriculums
datum	data
deer	deer or deers
diagnosis	diagnoses
die	dice or dies
dwarf	dwarves or dwarfs
ellipsis	ellipses
erratum	errata
faux pas	faux pas
fez	fezzes or fezes
fish	fish or fishes
focus	foci or focuses
foot	feet or foot
formula	formulae or formulas
fungus	fungi or funguses
genus	genera or genuses
goose	geese
graffito	graffiti
grouse	grouse or grouses
half	halves
hoof	hooves or hoofs
hypothesis	hypotheses
index	indices or indexes
larva	larvae or larvas
libretto	libretti or librettos
loaf	loaves
locus	loci
louse	lice
man	men
matrix	matrices or matrixes
medium	media or mediums
memorandum	memoranda or memorandums
minutia	minutiae
moose	moose
mouse	mice
nebula	nebulae or nebulas
nucleus	nuclei or nucleuses
oasis	oases
offspring	offspring or offsprings
opus	opera or opuses
ovum	ova
ox	oxen or ox
parenthesis	parentheses
phenomenon	phenomena or phenomenons
phylum	phyla
quiz	quizzes
radius	radii or radiuses
referendum	referenda or referendums
salmon	salmon or salmons
scarf	scarves or scarfs
self	selves
series	series
sheep	sheep
shrimp	shrimp or shrimps
species	species
stimulus	stimuli
stratum	strata
swine	swine
syllabus	syllabi or syllabuses
symposium	symposia or symposiums
synopsis	synopses
tableau	tableaux or tableaus
thesis	theses
thief	thieves
tooth	teeth
trout	trout or trouts
tuna	tuna or tunas
vertebra	vertebrae or vertebras
vertex	vertices or vertexes
vita	vitae
vortex	vortices or vortexes
wharf	wharves or wharfs
wife	wives
wolf	wolves
woman	women

Sources

• Crystal, David. «The Cambridge Encyclopedia of the English Language.» 3rd Edition, Cambridge University Press, January 24, 2019.
• Manser, Martin. «Penguin Writers Manual.» Penguin Reference Books, Stephen Curtis, Paperback, International Edition, UK ed. edition, Penguin UK, August 24, 2004.

Most countable nouns form the plural by adding the ending s/es. (The rules of adding s/es and the peculiarities of adding s/es to the final letters Y, O, F, FE and to compound nouns are described in the material Adding the Ending s/es to Nouns and Verbs in the section Writing.)

A limited number of nouns have irregular plural forms, for example, names of some animals, some words of Latin or Greek origin.

Irregular plural forms

Some nouns form their plural not by adding the ending s/es, but by changing the letters in the root of the word.

man – men;

woman – women;

child – children;

ox – oxen;

mouse – mice;

louse – lice;

foot – feet;

tooth – teeth;

goose – geese.

Note: The noun «brother» (a member of a family) has a regular plural form: brother – brothers. If the noun «brother» is used in the meaning «a fellow member», it may have the archaic irregular plural form «brethren» (fellow members).

The same singular and plural form

Some nouns have the same singular and plural form.

one sheep – two sheep;

a deer – two deer;

a bison – five bison;

a moose – three moose;

a swine – several swine;

a fish – two fish;

a dozen – two dozen;

an aircraft – two aircraft;

a means – means;

a series – two series;

a species – different species;

a corps [ko:r] – corps [ko:rz];

a headquarters – headquarters;

a crossroads – crossroads;

an alms – alms;

a gallows – gallows;

a barracks – barracks.

Singular or plural verb form

If a noun with the same singular and plural form is used as the subject of a sentence, the choice of the singular or plural verb form depends on the meaning of the noun.

If the noun is singular in meaning, the singular form of the verb is used. For example:

A deer is a graceful animal.

The aircraft is ready for the flight.

The UN headquarters is in New York.

If the noun is plural in meaning, the plural form of the verb is used. For example:

Three sheep were missing.

Deer are rare in these places.

Modern aircraft are powerful machines.

Note: Different kinds

The word «fish» and the names of some fish, for example, «cod, flatfish, salmon, trout», usually have the same singular and plural form, especially in ordinary speech and writing. For example: She bought several fish, including a trout and two salmon. He caught three trout. They had fish for dinner.

In scientific literature, the plural form of such nouns is also often the same as the singular form. For example: Numerous varieties of fish are found in tropical waters. Tropical fish are usually brightly colored. Bass, cod, salmon, sturgeon and trout abound in these rivers and lakes.

When referring to different kinds, species and varieties, such nouns in the plural often have the plural ending s/es in scientific literature: freshwater fishes; aquarium fishes; cods, flatfishes, salmons, trouts, etc. For example: Tropical fishes are usually brightly colored. All fishes have fins.

Some uncountable mass nouns may also be used in the plural when referring to different kinds and varieties, usually in scientific literature. For example: the teas of India; soft cheeses; stainless steels. (See Articles: Uncountable Nouns in the section Grammar.)

Note: Names of animals (birds, fish, etc.) may be used as a notion representing the whole class of such species; in such cases, the noun is used in the singular with the definite article «the». For example: The leopard lives in forests. The blue whale is the largest of all mammals. (See Specific Use of THE in the section Grammar.)

Only in the plural

Nouns that denote an indivisible pair of things are used in the plural and with a plural verb. Such nouns are often used with the phrase «a pair of».

jeans; trousers, pants, slacks;

shorts, tights, breeches;

pajamas, briefs, panties;

scissors, pliers, tongs, pincers, forceps;

glasses, spectacles.

Examples:

These jeans are too long for me.

Your trousers are in the bedroom closet.

Where are my glasses?

Where are my gym tights?

She bought two pairs of jeans and a pair of shorts.

There is a pair of scissors in the kitchen.

Note: The word «pantyhose» is used in the singular.

Where is my new pantyhose?

She bought four pairs of pantyhose.

Some other plural nouns

There are some other nouns with the ending s/es that are used only in the plural, take a plural verb, and have no singular form in the given meaning.

For example: clothes, arms (weapons), goods, troops, remains, savings, belongings. In some of such cases there is a singular form, but its meaning is different (for example: a troop; troops).

These clothes need washing.

He lost all his savings.

Various consumer goods are sold in this store.

Only in the singular

Some uncountable nouns have the ending «s» in their form but are used only in the singular. For example: news; names of some games (billiards, dominoes, checkers, cards); names of some diseases (measles, mumps). Scientific subjects are also singular: mathematics, physics, phonetics, linguistics, economics, politics.

If such nouns are in the function of the subject, the verb is used in the singular form. For example:

No news is good news. (proverb)

Billiards is an interesting game.

Measles is a serious disease.

Mathematics is his favorite subject.

Note: The word «money» is used in the singular: Where is my money? This money is mine. Money makes money. Money talks. Money is the root of all evil. The plural forms «moneys, monies» are used mostly in law terminology in the meaning «sums of money».

Note: Nouns ending in «ics»

As described above, uncountable nouns ending in «ics» are used only in the singular. But some of them have meanings in which they are used in the plural, though such use is not very common.

For example, «statistics» as a science is used in the singular (Statistics is a science); «statistics» as numerical data is used in the plural (These statistics are not correct).

Other nouns that may be used in the same way: acoustics, economics, politics, gymnastics. For example:

Acoustics is a branch of physics. The acoustics of this concert hall are excellent.

She studied economics in college. What are the economics of this project?

He is studying politics. What are his politics?

Latin and Greek plural forms

Some nouns of Latin or Greek origin have kept their Latin or Greek plural endings. The plural ending «es» as in the word «analyses» is pronounced [i:z]; the ending «i» as in the word «alumni» is pronounced [ai]; the ending «ae» as in «vertebrae» is pronounced [i:].

Nouns with Latin and Greek plural endings in the list below are divided into groups according to the ending in the singular. The English plural ending s/es is also used with some of these nouns; in such cases, two variants are given, and the variant with the English ending s/es is marked with the letter (E).

Generally (but not always), English variants of plural forms are more common in ordinary speech and writing, and Latin and Greek variants are more common in scientific and academic texts.

The first variant of the plural forms in the list below is the variant that is usually listed first in American dictionaries. In some cases dictionaries differ on which of the two variants is more common.

In a few cases, English and Latin plural forms are different in meaning. For example: radio antennas, an insect’s antennae; mass media (radio, TV, newspapers), spiritualistic mediums (people regarded as mediums).

Note: The noun «data», the plural of «datum», can be used as singular or plural in meaning: this data; these data; there is no data. The noun «agenda», originally the plural of «agendum», is generally used as a singular noun: today’s agenda; a lengthy agenda.

Group 1

analysis – analyses

axis – axes

basis – bases

crisis – crises

diagnosis – diagnoses

ellipsis – ellipses

emphasis – emphases

genesis – geneses

hypothesis – hypotheses

oasis – oases

parenthesis – parentheses

synopsis – synopses

synthesis – syntheses

thesis – theses

Group 2

abacus – abacuses (E), abaci

alumnus – alumni

apparatus – apparatus, apparatuses (E)

cactus – cactuses (E), cacti

calculus – calculi, calculuses (E)

corpus – corpora

eucalyptus – eucalyptuses (E), eucalypti

focus – focuses (E), foci

fungus – fungi, funguses (E)

genus – genera, genuses (E)

hippopotamus – hippopotamuses (E), hippopotami

nucleus – nuclei, nucleuses (E)

octopus – octopuses (E), octopi

papyrus – papyri, papyruses (E)

platypus – platypuses (E), platypi

radius – radii, radiuses (E)

rhombus – rhombuses (E), rhombi

stimulus – stimuli

stylus – styluses (E), styli

syllabus – syllabuses (E), syllabi

terminus – termini, terminuses (E)

Group 3

automaton – automatons (E), automata

criterion – criteria

phenomenon – phenomena

polyhedron – polyhedrons (E), polyhedra

octahedron – octahedrons (E), octahedra

tetrahedron – tetrahedrons (E), tetrahedra

Group 4

addendum – addenda

aquarium – aquariums (E), aquaria

arboretum – arboretums (E), arboreta

atrium – atria, atriums (E)

bacterium – bacteria

compendium – compendiums (E), compendia

curriculum – curriculums (E), curricula

datum – data

emporium – emporiums (E), emporia

equilibrium – equilibriums (E), equilibria

erratum – errata

forum – forums (E), fora

maximum – maximums (E), maxima

medium – media

medium – mediums

memorandum – memorandums (E), memoranda

millennium – millenniums (E), millennia

planetarium – planetariums (E), planetaria

podium – podiums (E), podia

spectrum – spectra, spectrums (E)

stadium – stadiums (E), stadia

sternum – sterna, sternums (E)

stratum – strata, stratums (E)

symposium – symposiums (E), symposia

terrarium – terrariums (E), terraria

vacuum – vacuums (E), vacua

vivarium – vivariums (E), vivaria

Group 5

alumna – alumnae

antenna – (radio) antennas

antenna – (insects’) antennae

charisma – charismata

dogma – dogmas (E), dogmata

enigma – enigmas (E), enigmata

formula – formulas (E), formulae

stigma – stigmata, stigmas (E)

vertebra – vertebrae, vertebras (E)

Group 6

apex – apexes (E), apices

appendix – appendixes (E), appendices

index – indexes (E), indices

matrix – matrices, matrixes (E)

vertex – vertexes (E), vertices

vortex – vortexes (E), vortices.

Существительные с неправильной формой множественного числа

Большинство исчисляемых существительных образуют множественное число прибавлением окончания s/es. (Правила прибавления s/es и особенности прибавления s/es к конечным буквам Y, O, F, FE и к сложным существительным описаны в материале Adding the Ending s/es to Nouns and Verbs в разделе Writing.)

Ограниченное число существительных имеют неправильные формы мн. числа, например, названия некоторых животных, некоторые слова латинского или греческого происхождения.

Неправильные формы мн. числа

Некоторые существительные образуют множественное число не прибавлением окончания s/es, а изменением букв в корне слова.

мужчина – мужчины;

женщина – женщины;

ребенок – дети;

бык – быки, рогатый скот;

мышь – мыши;

вошь – вши;

ступня – ступни;

зуб – зубы;

гусь – гуси.

Примечание: Существительное «brother» (член семьи) имеет правильную форму мн. числа: brother (брат) – brothers (братья). Если существительное «brother» употреблено в значении «собрат, сотоварищ», оно может иметь устаревшую неправильную форму мн. числа «brethren» (собратья).

Одна и та же форма ед. и мн. числа

Некоторые существительные имеют одну и ту же форму ед. и мн. числа.

одна овца – две овцы;

один олень – два оленя;

бизон – пять бизонов;

лось – три лося;

свинья – несколько свиней;

рыба – две рыбы;

дюжина – две дюжины;

воздушное судно – два воздушных судна;

средство – средства;

серия – две серии;

вид, род – разные виды;

корпус, организация – корпусы, организации;

штаб – штабы;

перекрёсток, пересечение дорог – перекрёстки;

подаяние – подаяния;

виселица – виселицы;

казарма, барак – казармы, бараки.

Форма глагола в ед. или мн. числе

Если существительное с одинаковой формой ед. и мн. числа употреблено как подлежащее, выбор формы ед. или мн. числа глагола зависит от значения существительного.

Если существительное в ед. числе по значению, употребляется форма ед. числа глагола. Например:

Олень – грациозное животное.

Самолет готов к полёту.

Штаб-квартира ООН находится в Нью-Йорке.

Если существительное во мн. числе по значению, употребляется форма мн. числа глагола. Например:

Три овцы исчезли.

Олени редки в этих местах.

Современные самолёты – мощные машины.

Примечание: Различные виды

Слово «fish» и названия некоторых рыб, например, «cod, flatfish, salmon, trout», обычно имеют одну и ту же форму ед. и мн. числа, особенно в обычной устной и письменной речи. Например: Она купила несколько рыб, включая (одну) форель и двух лососей. Он поймал три форели. У них была рыба на обед.

В научной литературе, форма мн. числа таких существительных часто тоже одинакова с формой ед. числа. Например: Многочисленные виды рыб встречаются в тропических водах. Тропические рыбы обычно ярко окрашены. Окунь, треска, лосось, осётр и форель в изобилии встречаются в этих реках и озёрах.

Если имеются в виду различные виды и разновидности, такие существительные во мн. числе часто имеют окончание мн. числа s/es в научной литературе: freshwater fishes (виды пресноводных рыб); aquarium fishes (виды аквариумных рыб); cods, flatfishes, salmons, trouts и т.д. Например: Тропические рыбы обычно ярко окрашены. Все рыбы имеют плавники.

Некоторые неисчисляемые существительные массы могут тоже употребляться во мн. числе, когда имеются в виду различные виды, сорта, разновидности, обычно в научной литературе. Например: the teas of India (виды индийского чая); soft cheeses (мягкие сыры); stainless steels (виды нержавеющей стали). (См. Articles: Uncountable Nouns в разделе Grammar.)

Примечание: Названия животных (птиц, рыб и т.д.) могут употребляться как понятие, представляющее целый класс такого вида; в таких случаях, это существительное употребляется в ед. числе с определённым артиклем «the». Например: Леопард живёт в лесах. Голубой кит – самое крупное из всех млекопитающих. (См. Specific Use of THE в разделе Grammar.)

Только во мн. числе

Существительные, которые обозначают нераздельную пару, употребляются во мн. числе и с глаголом мн. числа. Такие существительные часто употребляются с фразой «a pair of» (пара).

джинсы; брюки;

шорты, колготки / трико, бриджи;

пижама, трусы, трусики;

ножницы, плоскогубцы, щипцы, щипчики, хирургические щипцы / пинцет;

очки.

Примеры:

Эти джинсы слишком длинные для меня.

Твои брюки во встроенном шкафу в спальне.

Где мои очки?

Где мои спортивные колготки / трико?

Она купила две пары джинсов и пару шортов.

На кухне есть пара ножниц.

Примечание: Слово «pantyhose» (колготки) употребляется в ед. числе.

Где мои новые колготки?

Она купила четыре пары колготок.

Некоторые другие существительные мн. числа

Есть некоторые другие существительные с окончанием s/es, которые употребляются только во мн. числе, принимают глагол во мн. числе и не имеют формы ед. числа в данном значении.

Например: clothes, arms (оружие), goods, troops, remains, savings, belongings. В некоторых таких случаях есть форма ед. числа, но её значение другое (например: группа людей; войска).

Эту одежду нужно постирать.

Он потерял все свои сбережения.

Различные потребительские товары продаются в этом магазине.

Только в ед. числе

Некоторые неисчисляемые существительные имеют окончание «s» по форме, но употребляются только в ед. числе. Например: news (новость); названия некоторых игр (бильярд, домино, шашки, карты); названия некоторых болезней (корь, свинка). Научные предметы тоже в ед. числе: математика, физика, фонетика, лингвистика, экономика, политика.

Если такие существительные в функции подлежащего, глагол употребляется в форме ед. числа. Например:

Отсутствие новостей – хорошая новость. (пословица)

Бильярд – интересная игра.

Корь – серьёзная болезнь.

Математика – его любимый предмет.

Примечание: Слово «money» употребляется в ед. числе: Where is my money? (Где мои деньги?) This money is mine. (Эти деньги мои.) Money makes money. (Деньги к деньгам идут.) Money talks. (С деньгами легче добиться.) Money is the root of all evil. (Деньги корень зла.) Формы мн. числа «moneys, monies» употребляются в основном в юридической терминологии в значении «денежные суммы».

Примечание: Существительные с окончанием «ics»

Как описано выше, неисчисляемые существительные, оканчивающиеся на «ics», употребляются только в ед. числе. Но некоторые из них имеют значения, в которых они употребляются во мн. числе, хотя такое употребление не очень распространено.

Например, «statistics» как наука употребляется в ед. числе (Statistics is a science); «statistics» как численные данные – во мн. числе (These statistics are not correct).

Другие существительные, которые могут употребляться таким же образом: acoustics, economics, politics, gymnastics. Например:

Акустика – это один из разделов физики. Акустические свойства этого концертного зала отличные.

Она изучала экономику в колледже. Каковы экономические характеристики этого проекта?

Он изучает политику. Каковы его политические взгляды?

Латинские и греческие формы мн. числа

Некоторые существительные латинского или греческого происхождения сохранили свои латинские или греческие окончания мн. числа. Окончание мн. числа «es» как в слове «analyses» произносится [i:z]; окончание «i» как в слове «alumni» произносится [ai]; окончание «ae» как в слове «vertebrae» произносится [i:].

Существительные с латинскими и греческими окончаниями мн. числа в списке ниже разделены на группы по окончанию ед. числа. Английское окончание мн. числа s/es также употребляется с некоторыми из этих существительных; в таких случаях даны два варианта, а вариант с английским окончанием s/es отмечен буквой (E).

Обычно (но не всегда), английские варианты форм мн. числа более употребительны в обычной устной и письменной речи, а латинские и греческие варианты более употребительны в научных и академических текстах.

Первый вариант форм мн. числа в списке ниже – это вариант, который обычно указывается первым в американских словарях. В некоторых случаях словари расходятся во мнениях, который из двух вариантов более употребителен.

В некоторых случаях, английская и латинская формы мн. числа различны по значению. Например: radio antennas, an insect’s antennae; mass media (радио, ТВ, газеты), spiritualistic mediums (люди, рассматриваемые как медиумы).

Примечание: Существительное «data» (данные), мн. число от «datum», может употребляться как ед. или мн. число по значению: this data; these data; there is no data. Существительное «agenda» (повестка дня), изначально мн. число от «agendum», обычно употребляется как существительное ед. числа: today’s agenda; a lengthy agenda.

Группа 1

анализ – анализы

ось – оси

базис, основа – основы

кризис – кризисы

диагноз – диагнозы

эллипсис, многоточие – многоточия

эмфаза, подчёркивание, выделение

происхождение, генезис

гипотеза – гипотезы

оазис – оазисы

круглая скобка – круглые скобки

синопсис, краткий обзор – краткие обзоры

синтез – синтезы

тезис, диссертация – тезисы, диссертации

Группа 2

счёты (как один предмет) – счёты (мн.ч.)

выпускник, бывший студент – выпускники

аппарат – аппараты

кактус – кактусы

исчисление – исчисления

корпус, свод, тело – корпусы

эвкалипт – эвкалипты

фокус – фокусы

грибок, плесень – грибки

род, вид, сорт – виды, сорта

гиппопотам – гиппопотамы

ядро – ядра

осьминог – осьминоги

папирус – папирусы

утконос – утконосы

радиус – радиусы

ромб – ромбы

стимул – стимулы

(техн.) игла, перо, щуп – иглы, щупы

учебный план – учебные планы

конец, конечный пункт – конечные пункты

Группа 3

автомат, робот – автоматы, роботы

критерий – критерии

феномен – феномены

многогранник – многогранники

октаэдр, восьмигранник – октаэдры

тетраэдр, четырёхгранник – тетраэдры

Группа 4

приложение – приложения

аквариум – аквариумы

дендрарий – дендрарии

атрий, атриум – атриумы

бактерия – бактерии

компендиум – компендиумы

программа (обучения) – программы (обучения)

данное – данные

торговый центр – торговые центры

равновесие, уравновешенность

опечатка – опечатки

форум – форумы

максимум – максимумы

способ, средство (связи) – средства (связи)

медиум – медиумы

меморандум – меморандумы

тысячелетие – тысячелетия

планетарий – планетарии

подиум – подиумы

спектр – спектры

стадион – стадионы

грудина – грудины

слой, пласт – слои, пласты

симпозиум – симпозиумы

террарий, террариум – террарии, террариумы

вакуум – вакуумы

виварий – виварии

Группа 5

выпускница – выпускницы

антенна – (радио) антенны

усик – усики (насекомых)

харизма

догма – догмы

загадка, необъяснимое явление – загадки

формула – формулы

клеймо, пятно – стигмы, стигматы, пятна

позвонок – позвонки

Группа 6

высшая точка, вершина – вершины

приложение – приложения

индекс – индексы

матрица, форма – матрицы, формы

вершина, макушка – вершины

водоворот, вихрь – водовороты.

The table below lists English words that have irregular plurals.

Rules[edit]

Not included are words that follow any of the following rules:

1. Words that add -s, which are regular plurals
2. Words that end in -ch, -o, -s, -sh, -x, -z
3. Symbols or letters, which often add -‘s
4. Words that are invariant in the plural (eg, deer, series)
5. Words from Latin that end in -a change -a to -ae (eg, formula becomes formulae in the mathematical and chemical senses)
6. Words from Latin that end in -ex change -ex to -ices (eg, vortex becomes vortices)
7. Words that end in -f or -fe change -f or -fe to -ves (eg, calf becomes calves; knife becomes knives)
8. Words that end in -ful that add an s after the -ful (eg, spoonful becomes spoonfuls; note that spoonsful is incorrect)
9. Words from Latin that end in -is change -is to -es (eg, thesis becomes theses)
10. Words from Latin that end in -ix change -ix to -ices (eg, matrix becomes matrices)
11. Words from Greek that end in -ma change -ma to -mata (eg, stigma becomes stigmata in all senses but the sense of «disgrace»)
12. Words from Latin that end in -nx change -nx to -nges (eg, meninx becomes meninges)
13. Words from Greek that end in -on change -on to -a (eg, polyhedron becomes polyhedra)
14. Words that end in -s or -ese denoting a national of a particular country (eg, Swiss and Chinese)
15. Words from French that end in -u add an x (eg, château becomes châteaux)
16. Words from Latin that end in -um change -um to -a (eg, minimum becomes minima)
17. Words from Latin that end in -us change -us to -i or -era (eg, radius becomes radii; genus becomes genera; but note octopus is different)
18. Words that end in -y preceded by a consonant change -y to -ies (eg, baby becomes babies)
19. Words from Hebrew that add -im or -ot (eg, cherub becomes cherubim)

Source: Wikipedia article on English plurals, which you can see for much more information.

Some of words of foreign origin that have the endings above can form or always form their plurals regularly. The list above should therefore be considered as a guide only. See particular words to determine their plurals.

Umlaut[edit]

The following plurals exhibit umlaut, meaning that they are inflected by changing the vowel, as in man/men. These stem from the stem vowel being mutated due to a following /i/ contained in Germanic consonant stem plurals that later vanished.

Singular	Plural	Notes
foot	feet	The plural foot is used colloquially in the sense of the unit of distance
goose	geese	The plural of mongoose is mongooses
louse	lice	Also for the names of animals ending in -louse, such as woodlouse, which becomes woodlice
man	men	Also for nouns ending in -man in the sense of a particular type of man, such as postman or Frenchman; words ending in -man that have another origin are regular (eg, ataman becomes atamans; shaman becomes shamans)
mouse	mice	Also applies to the names of other animals that end in -mouse, such as dormouse and titmouse, which become dormice and titmice respectively; the plural mouses is sometimes used for the computer peripheral
tooth	teeth	Also for nouns ending in -tooth, such as eyetooth, which becomes eyeteeth
woman	women	Also for nouns ending in -woman in the sense of a particular type of woman, such as policewoman or Englishwoman

Weak noun[edit]

The following plurals are relics of Old English weak noun inflection, where the plural was formed by suffixing -an/-ena/-um, depending on case, which yields the -en ending.

“oxen” is ox-en, while “children” is in fact a double plural: “cild-ru-en”, where -ru is a strong noun plural, and -en is a weak noun plural.

boxen and Vaxen are humorous computing slang formed by the same rule.

Singular	Plural	Notes
child	children	Also for nouns ending in -child in the sense of a particular type of child, such as schoolchild
ox	oxen	Also applies to the names of other animals that end in ox, such as musk-ox

Suppletive[edit]

A suppletive plural is a plural whose root is different from the root of the singular, i.e., not from the same underlying word.

Singular	Plural	Notes
person	people	Also for nouns ending in -person, such as chairperson, which becomes chairpeople. In formal contexts, the plural is persons (and similarly for nouns ending in -person); people is also a singular noun in the sense of a community of people

Devoiced regular plural endings[edit]

“pence” is a contraction of “pennies”, collective plural of “penny”.

Singular	Plural	Notes
die	dice	in the sense of a numbered cube used in games.
penny	pence	Also for multiples of a penny, such as sixpence. Pence, a British usage, is used only the sense of an amount of money; in the sense of a number of coins worth a penny each, the plural is pennies

See also[edit]

• English plural: Irregular plurals
• Wikipedia article on hypercorrection – includes information on some incorrectly formed plurals

Usually it is very easy to make plural nouns from singular nouns by following some standard rules such as adding -s or -es to the end of the word. However, there are some nouns that don’t seem to follow the rules. Such nouns are called irregular nouns. That means they don’t become plural the “regular” way.

Here is a list of those irregular plural nouns.

Irregular plural nouns that replace end letter ‘f’ & ‘fe’ with ves:

Singular: Plural:

calf calves

elf elves

knife knives

leaf leaves

loaf loaves

shelf shelves

wolf wolves

Irregular plural nouns made by changing vowels also called Apophonic plurals:

Singular: Plural:

analysis analyses

dormouse dormice

foot feet

goose geese

louse lice

man men

mouse mice

neurosis neuroses

oasis oases

tooth teeth

thesis theses

woman women

Irregular plural nouns made by changing the word, or adding a different ending:

Singular: Plural:

abyss abysses

alumnus alumni

Appendix appendices

aquarium aquaria

bacterium bacteria

cactus cacti

château chateaux

child children

ox oxen

Irregular plural nouns that have the same spelling as their singular form (most of them are animals):

Singular: Plural:

Bison Bison

Buffalo buffalo

Deer deer

Duck duck

Pants Pants

Pike pike

Salmon salmon

Scissors scissors

series series

Sheep sheep

Squid squid

Swine swine

Trout trout

Animal nouns that become plural by keeping the same spelling as the singular form or by adding an -s or -es.

Singular: Plural:

cod cod or cods

fish fish or fishes

hoax hoax or hoaxes

quail quail or quails

shrimp shrimp or shrimps

Singular: Plural:

index indexes

moose moose

mouse mice

nucleus nuclei

octopus octopi

person people

plateau plateaux

runner-up runners-up

son-in-law sons-in-law

species species

waltz waltzes

Irregular plural nouns that replace end word -a with -ae or -s:

Singular: Plural:

alumna alumnae

Encyclopaedia encyclopædia

Encyclopedia encyclopaedias / encyclopedias

formula formulae/formulas

Irregular plural nouns that replace end word -ex or -ix with -ices or just adds -es:

Singular: Plural:

index indices or indexes

matrix matrices

vertex vertices

Irregular plural nouns that replace end word -is with -es:

Singular: Plural:

axis axes

crisis crises

emphasis emphases

nemesis nemeses

testis testes

Irregular plural nouns that replace end word -is with -es:

Singular: Plural:

series series

species species

Irregular plural nouns that replace end word -um with -a:

Singular: Plural:

Addendum addenda

agendum agenda or agendas

corrigendum corrigenda

datum data

forum fora/forums

medium media or mediums

memorandum memoranda/memorandums

millennium millennia

ovum ova

spectrum spectra

Irregular plural nouns that replace end word -us with -i or -era or -ora, or just adds -es:

Singular: Plural:

Alumnus alumni

campus campuses or campi

census censuses

circus circuses

corpus corpora

curriculum curricula

focus foci

fungus fungi

genus genera

hippopotamus hippopotami/ hippopotamuses

meatus meatus/meatuses

octopus octopuses octopi/ octopodes

prospectus prospectuses

platypus platypuses / platypodes

radius radii

status status/ statuses

stylus styli

syllabus syllabi

succubus succubi

terminus termini/terminuses

uterus uteri/uteruses

virus viruses

viscus viscera

Irregular plural nouns that replace end word –on with –a:

Singular: Plural:

automaton automata

criterion criteria

phenomenon phenomena

polyhedron polyhedral

Irregular plural nouns that replace end word –as with –ntes and -es:

Singular: Plural:

Atlas Atlantes (it is for the statues of the Titan)

atlas atlases (map collections)

Irregular plural nouns that replace end word –ma with -mata or -s:

Singular: Plural:

Anathema anathemata or anathemas

dogma dogmata or dogmas

lemma lemmata or lemmas

schema schemata or schemas

stigma stigmata or stigmas

stoma stomata or stomas

Irregular plural nouns made by adding -x or -s (These words are mostly of different language):

Singular: Plural:

beau beaux or beaus

bureau bureaux or bureaus

château châteaux or châteaus

tableau tableaux or tableaus

Irregular Plurals of compound nouns:

Singular: Plural:

attorney general attorneys general

chief of staff chiefs of staff

court martial courts martial

director general directors general

governor-general governors-general

head banger head bangers

minister-president ministers-president

passerby passersby

seaman seamen

ship of the line ships of the line

son-in-law sons-in-law

Irregular Plurals of compound nouns with two heads:

Singular: Plural:

man-child men-children

manservant menservants

woman doctor women doctors

Irregular Plurals of compound nouns with two heads, but only the final head will be pluralize:

Singular: Plural:

brigadier general brigadier generals

city-state city-states

major general major generals

nurse-practitioner nurse-practitioners

scholar-poet scholar-poets

Irregular Plurals of compound nouns with three or more words, a term functioning as a head, only that term is pluralized:

Singular: Plural:

man-about-town men-about-town

man-of-war men-of-war

woman of the street women of the street

Irregular Plurals of compound nouns with three or more words, a term functioning as a head is in the beginning and at the end, either term can be pluralized:

Singular: Plural:

ham on rye hams on rye or ham-on-ryes

jack-in-the-box jacks-in-the-box or jack-in-the-boxes

jack-in-the-pulpit jacks-in-the-pulpit or jack-in-the-pulpits

Few extended compounds, both the terms may be pluralized:

Singular: Plural:

head of state heads of states/heads of state

son of a bitch sons of bitches/sons-of-a-bitch

Besides, there are additional plural nouns whose singular forms exist, but hardly their plurals are used, like:

Singular: Plural:

nuptial nuptials

phalanx phalanges

tiding tidings

victual victuals

viscus viscera

Thanks for reading! Hope this list helps!!