Compound Words
Here are some examples of compound noun types and their written forms.
Compound nouns:
- noun + noun – (these are the most common) – housewife, suitcase, seafood. database
- noun + er (noun or verb) – housekeeper, backwater, screwdriver, eye-opener
- noun + verb-ing – skydiving, window shopping, film-making, trainspotting (train spotting)
- verb+particle – handout, giveaway, checkout, lookout
- particle-verb – income, output, bypass, outsource
- adj + noun – greenhouse, blackbird, whiteboard, real estate
- verb + noun – swimsuit, driving licence, rocking chair, washing machine
- three word compounds – washing-up-liquid, sister-in-law, birds-of-prey
Making compound nouns plural:
Most compound nouns follow the normal convention that would be used if the final part of the compound were pluralised:
- suitcases, handouts, swimsuits
- housewives, bypasses
Where compounds end in the prepositions by or on the first word in made plural:
- passer-by passers-by
- hanger-on hangers-on
Where compounds have three parts the first word is made plural (if this word is the defining word):
- sisters-in-law but washing-up-liquids
Quiz: Plurals- Compound Nouns
Plural forms of compound nouns
In general we make the plural of a compound noun by adding -s to the “base word” (the most “significant” word). Look at these examples:
singular | plural |
a tennis shoe | three tennis shoes |
one assistant headmaster | five assistant headmasters |
the sergeant major | some sergeants major |
a mother-in-law | two mothers-in-law |
an assistant secretary of state | three assistant secretaries of state |
my toothbrush | our toothbrushes |
a woman-doctor | four women-doctors |
a doctor of philosophy | two doctors of philosophy |
a passerby, a passer-by | two passersby, two passers-by |