Compound nouns are nouns made up of two or more words: Portafortuna (lucky charm), Caporedattore (editor-in-chief), Dopocena (after dinner), Messinscena (staging).
The elements that compose them can belong to different grammatical categories: nouns, adjectives, verbs, adverbs, and prepositions.
Compound nouns form the plural depending on the type of words from which they are formed.
1. Noun + Noun.
The plural is formed as if they were simple nouns, only the ending changes:
Singular: L’arcobaleno (rainbow) – La ferrovia (railway) – Il cavolfiore (cauliflower).
Plural: Gli arcobaleni – Le ferrovie – I cavolfiori.
2. Noun + Adjective.
Both elements are put in the plural.
Singular: La cassaforte (The safe) – Il pellerossa (Red Indian) – Il caposaldo (cornerstone).
Plural: Le casseforti – I pellirosse – I capisaldi.
Exception:
Singular: Il palcoscenico (stage) – Il pianoforte (piano).
Plural: I palcoscenici – I pianoforti.
3. Adjective + Noun.
Only the second element is put in the plural.
Singular: Il francobollo (stamp) – Il bassorilievo (bas–relief).
Plural: I francobolli – I bassorilievi.
4. Preposition + Noun.
They normally modify the ending.
Singular: Il contrabbando (smuggling) La soprattassa (surcharge) Il sottufficiale (non–commissioned officer).
Plural: I contrabbandi – Le soprattasse – I sottufficiali.
Or they remain unchanged.
Singular: Il doposcuola (afterschool) – Il fuoribordo (outboard) – Il sottoscala (understairs).
Plural: I doposcuola – I fuoribordo – I sottoscala.
5. Verb + Plural Noun.
Both elements remain unchanged.
Singular: Il cavatappi (corkscrew) – L’apriscatole (The can opener) – Il guastafeste (mood breaker) – Il portalettere (postman).
Plural: I cavatappi – Gli apriscatole – I guastafeste – I portalettere.
6. Verb + singular feminine noun.
Both elements remain unchanged.
Singular: Il portacenere (ashtray) – Il cavalcavia (overpass) – Il parapioggia (rain cover) Il bucaneve (snowdrop).
Plural: I portacenere – I cavalcavia – I parapioggia – I bucaneve.
7. Verb + singular masculine noun.
Only the second element is plural.
Singular: Il portafoglio (wallet) – Il passaporto (passport) – Il battibecco (bickering).
Plural: I portafogli – I passaporti – I battibecchi.
8. Verb + Verb.
Both elements remain unchanged.
Singular: Il dormiveglia (half asleep) – Il saliscendi (ups and downs) – Il parapiglia (turmoil).
Plural: I dormiveglia – I saliscendi – I parapiglia.
I nomi composti con capo- / Compound nouns with capo-.
1. When capo- indicates ‘he who is the head of something’, and the second element is a name of a thing or a group of individuals, the plural is formed by modifying the ending of capo:
Singular: Il capofamiglia (householder) – Il capogruppo (group leader) – Il caporeparto (Department head) – Il capobanda (ringleader) – Il caposquadra (foreman) – Il capostazione (stationmaster) – Il capoufficio (head office).
Plural: I capifamiglia – I capogruppo – I capireparto – I capibanda – I capisquadra – I capistazione – I capiufficio.
2. when capo- indicates ‘he who is someone’s boss’ and the second word is a person’s name, the plural is formed by modifying the ending of the second element:
Singular: Il capocuoco (chef) – Il caporedattore (Chief Editor) – Il capocomico (comedian).
Plural: I capocuochi – I caporedattori – I capocomici.
Or when it indicates ‘something that is pre-eminent, excellent.
Singular: Il capolavoro (masterpiece) – Il capoluogo (capital).
Plural: I capolavori – I capoluoghi.
3. In the plural of feminine nouns capo- always remains unchanged:
Singular: La caposala (head nurse) – La caporedattrice (editor–in–chief) – La caporeparto (Department head) – La capoinfermiera (head nurse).
Plural: Le caposala Le caporedattrici Le caporeparto Le capoinfermiera.
Exception:
Singular: La caporedattrice (editor–in–chief).
Plural: Le caporedattrici.