GRAMMAR
The Plural of Compound Nouns
How to form the plural of compound nouns
Forming the plural of compound nouns might be confusing for some. Before presenting some quick tips to form these compounds, let's review what compound nouns are first.
Compound Nouns
A compound noun is a noun made up of two or more words (e.g. toothpaste, haircut or daughter-in-law). Most compound nouns can be formed as follows:
| Forms | Examples |
|---|---|
| noun + noun | train station |
| noun + adjective | handful |
| adjective + noun | blackberry full moon |
| verb (ing) + noun | breakwater swimming pool |
| noun + verb (ing) | haircut skydiving |
| verb + preposition | check-in |
| noun + preposition | passer-by |
| preposition + noun | underground |
| noun + preposition + noun | father-in-law |
As you can see from the examples above, some compound nouns are spelled as one word (e.g. handful), but others with hyphens (e.g. father-in-law) or separated by a space (e.g. full moon).
Forming the plural of compound nouns
The plurals of compound nouns are generally formed by adding 's' to the principal word (i.e. the most significant word in the compound), also called the head of the compound. The head informs us about what the compound refers to. The other elements of the compound modify the head and are called the head's dependents.
Examples:
| compounds | head | plural |
|---|---|---|
| car park | park | car parks |
| blackboard | board | blackboards |
| mother-in-law | mother | mothers-in-law |
| taxi driver | driver | taxi drivers |
Compound nouns with -ful
Compound nouns with '-ful' (e.g. truckful, handful) may have two possible plurals. The 's' can be added either t:o
- the head noun (e.g. trucksful, handsful)
- or to '-ful ' (e.g. truckfuls, handfuls).
It is just a question of consistency.
More examples:
| Compound nouns with '-ful' | Plural | |
|---|---|---|
| handful | handsful | handfuls |
| mouthful | mouthsful | mouthfuls |
| spoonful | spoonsful | spoonfuls |
| bucketful | bucketsful | bucketfuls |
| cupful | cupsful | cupfuls |
| truckful | trucksful | truckfuls |
Compound nouns ending in a preposition
When the compound is formed with a noun and a preposition, (e.g. passer-by), the plural is formed by adding an 's' to the noun.
Examples:
| Compound Noun | Plural |
|---|---|
| passer-by | passers-by |
| hanger-on | hangers-on |
When neither element of a compound is a noun, the plural is formed by adding 's' to the last word. For example, the compound noun 'grown-up' is made of the word 'grown', which is the past participle of the verb 'grow', and the preposition 'up'. The plural of 'grown-up' is formed by adding 's' to 'up' (i.e. 'grown-ups).
More examples:
| Compound Noun | Plural |
|---|---|
| grown-up | grown-ups |
| go-between | go-betweens |
| check-in | check-ins |
| higher-up | higher-ups |
| also-ran | also-rans |
