English — Compound and noun-noun combinations
English often turns one noun into a modifier of another: a bus stop, a shoe shop. The first noun acts like an adjective and stays singular, even when the meaning is plural.
How it works
In a noun-noun combination the first noun usually modifies the second in the singular: a bus stop (a stop for buses), a shoe shop. A compound modifier such as five-year-old also keeps its noun singular: a five-year-old boy. Some compounds expressing possession or a link to people use the 's form: a children's book, a women's magazine.
Examples
| Form | Structure | Meaning |
|---|---|---|
| a bus stop | noun + noun, first singular | a stop for buses |
| a shoe shop | noun + noun, first singular | a shop that sells shoes |
| a five-year-old boy | number + noun, singular in compound | a boy who is five years old |
| a toothbrush | closed compound (written as one word) | a brush for the teeth |
| a children's book | 's compound (irregular plural + 's) | a book for children |
| a women's magazine | 's compound (irregular plural + 's) | a magazine for women |
Good to know
The first noun is usually singular even when the sense is plural: say a shoe shop and a three-hour trip, not "a shoes shop" or "a three-hours trip". Some nouns keep their plural (a sports car, a clothes shop), and some compounds with irregular plurals of people use 's (a children's book, a men's room).