Is door a compound word

Nouns can be combined with many different words to form compound nouns, the core noun is modified as though with an adjective. Compound nouns are treated like a single unit, so the entire group of words take the position of a regular noun, and any modifiers come before or after the whole compound noun.

• I danced with the Prime Minister’s daughter.
• The Prime Minister’s daughter is not a good dancer.

However, more consideration must be given to how compound nouns are formed, and the word order within these structures.

Single word or simple compound nouns

Compound nouns formed with adjectives at the end are often combined into a simple noun, for example words using suffixes such as ‘ful’ (a form of ‘full’). Similarly this happens when combining with a noun that represent quantities, such as ‘load’.

• bagful (a quantity that fills a bag)
• truckload (a quantity that fills a truck)

This also happens with nouns that are combined with a verb, often to describe an activity or event or an object used for a particular activity:

• haircut
• sunset
• skateboard

And with prepositions and prepositional phrases, which usually describe a noun with an inherent relationship:

• sister-in-law
• downtown

With all these examples, the word order is very simple as they are usually compound nouns in the form of a single word, or are collocations that should not be separated.

Compound nouns with two or more words

Compound nouns are also formed with nouns, adjectives, prepositions and verbs placed before a noun. Again, these are treated as one idea, taking the place in the sentence of a noun, but it is important to pay attention to the order of words within a compound noun.

The first word, whether a noun, adjective, verb or preposition, normally describes the final noun.

• cat food (a kind of food, for cats)
• car door (a type of door, belonging to a car)
• swimming pool (a type of pool, for swimming)
• full moon (a type of moon, when it is full)

Compound nouns must follow this word order or it will not make sense – a door car, for example, would mean a car made of doors. In some cases, the words can be reversed for a logical, but different, meaning:

• horse race (a type of race, with horses)
• race horse (a type of horse, for races)

As the second word in these compound nouns represents the main idea, it can be useful to think of the preceding word as an object; additional, describing information.

• football shirt – a shirt worn for football
• finance book – a book used for finances
• London taxi – a taxi from London
• blackboard – a board that is black

With combinations of nouns, because the first noun describes a purpose, and not quantities, it is always in singular form.

• wedding ring / wedding rings

Any articles come before both the entire compound noun, but are based on the final noun, not any other nouns in the compound. For example, sun does not require the here:

• Do you have some sun cream? (some cream)
• Pass me the sun cream. (the specific cream)

Note that not all nouns can form compound by simply putting one word in front of another. Sometimes nouns must be linked with prepositions:

• a sense of longing (not a longing sense)

Compound nouns with more than two nouns

Sometimes compound nouns of more than one word are used to describe additional nouns, which can form more complex compound nouns, similar to placing multiple adjectives in front of a noun. Additional information describes the noun (or compound noun) it comes directly before. Note that the main noun will be the final word in a series, so adding words at the end of these structures will change the noun:

• sea creature analysis (a piece of analysis)
• sea creature analysis centre (a location)
• sea creature analysis centre report (a piece of writing)

If the final noun stays in the same position, additional words will change the description of the same noun:

• creature analysis
• sea creature analysis
• sea creature egg analysis
• Mediterranean Sea creature egg analysis

In this example, these are all types of analysis.

This is a brief introduction to compound nouns, mainly focusing on the idea of the word order. Individual nouns and structures can become more complex and in some cases it is necessary to use prepositional phrases and complements to describe ideas, instead of merely placing one word in front of another. This is explored more fully in my follow up article, all about noun complements.