Grammar › Nouns & Determiners › Compound Nouns
Compound Nouns
A compound noun combines words into one idea. Key rules:
- The first noun is like an adjective and stays singular — a car park, a toothbrush.
- Only the last word is made plural — bus stops, swimming pools.
- Written as one word, two words, or hyphenated — depends on the item.
Numbers + noun before another noun are singular and hyphenated: a ten-year-old boy, a two-hour film.
How compound nouns work
Two nouns join to make one idea. The first noun describes the second and stays singular.
| Compound | Note | Plural |
|---|---|---|
| bus stop | two words | bus stops |
| toothbrush | one word | toothbrushes |
| shoe shop | first noun singular | shoe shops |
| mother-in-law | hyphenated | mothers-in-law |
| ten-year-old | number + noun (singular) | ten-year-olds |
When and how to use them
1. First noun stays singular
- a book shelf, a car park, a coffee cup (not books shelf, cars park).
2. Only the last word takes the plural
- three bus stops, two swimming pools, some toothbrushes.
3. Numbers become singular modifiers
- a five-minute break, a two-hour film, a six-year-old child.
⚠️ Compare the noun and the modifier: The walk takes five minutes, but It’s a five-minute walk (singular, hyphenated before the noun).
Common mistakes
1. Plural first noun. a shoes shop → a shoe shop.
2. Plural in the number modifier. a ten-minutes walk → a ten-minute walk.
3. Pluralising the wrong part. mother-in-laws → mothers-in-law. Pro tip: keep the first noun singular; make only the last word plural.
✏️ Practice: Compound Nouns
1. I bought new shoes at the ___ .
2. There are three ___ on this street.
3. It's only a ___ walk from here.
4. Both my ___ came to the wedding.
5. Can you pass me a ___ ?
6. We stayed in a hotel with two ___ .
7. She's a ___ girl.
8. Put your dirty clothes in the ___ .
9. Correct this: 'It's a three-days trip.'
10. In a compound noun, which part is normally made plural?
Frequently asked questions
Why is it 'a shoe shop', not 'a shoes shop'?
The first noun acts like an adjective, so it stays singular: a shoe shop, a book shelf, a tooth brush — even though it sells shoes or holds books.
Which part becomes plural?
Only the last word: bus stops, car parks, toothbrushes. For 'mother-in-law' the plural is 'mothers-in-law' (the main noun is 'mother').
One word, two words, or a hyphen?
It varies by item and there's no single rule: toothbrush (one), bus stop (two), mother-in-law (hyphen). Check a dictionary if unsure.
Why 'a five-minute walk', not 'a five-minutes walk'?
When a number + noun describes another noun, it becomes a singular, hyphenated adjective: a five-minute walk, a three-day trip.
👩🏫 For teachers
CEFR objectives for “Compound Nouns”:
- Can form compound nouns keeping the first noun singular (CEFR B1).
- Can pluralise only the final element.
- Can use hyphenated number + noun modifiers (a two-hour delay).
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