Plural of Compound Nouns

A compound noun is a noun made up of a combination of several elements. The plural form varies according to the combination of those elements.

When these elements are variable words (adjectives, nouns, participles), they may take the plural form. When these elements are invariable words (adverbs, conjunctions, prepositions, verbs), they are invariable. The following general rules will help:

1. When a compound noun is written as a single word, the word is treated as a single noun and the plural is formed by adding the plural endings: le pourboire/les pourboires (tip)
2. When a compound noun is formed of an adjective + a noun or a noun + a noun, both add the plural endings: le beau-père/les beaux-pères (father-in-law)
   le chou-fleur/les choux-fleurs (cauliflower)
3. When a compound noun is formed of an adjective + an adjective, both elements add the plural endings: un nouveau-né/des nouveaux-nés (newborn)
4. When a compound noun is formed of a noun + a prepositional phrase, only the noun adds the plural ending: un arc-en-ciel/des arcs-en-ciel (rainbow)
5. When a compound noun is formed of a verb + its object noun, the noun adds the plural ending: un essuie-glace/ des essuie-glaces (windshield wiper)
   un coupe-papier/ des coupe-papiers (paper-knife)
6. When a compound noun is formed of two invariable components, the plural is the same as the singular: un passe-partout/des passe-partout (master key)

See Also:

• Nouns
• Singular and Plurals Nouns
• Common Nouns
• Proper Nouns
• Noncount Nouns
• Gender of Nouns
• Noun Formation
• Noun Phrases
• Noun Clauses
• Articles