Compound nouns in Romanian are usually joined by a hyphen. Forming their plural depends on the types of words inside the compound. Importantly, definite articles attach to whichever part is the main "head" noun.
Prefix + Noun: Only the Second Word Pluralizes
If the first part of a compound is invariable—like prim- (first)—it never changes. Only the second word takes the plural form and the definite article.
| The two prime ministers often meet in the capital. | Cei doi prim-miniștri se întâlnesc adesea în capitală. |
| They are the new prime ministers. | Ei sunt noii prim-miniștri. |
Noun + Adjective: Both Words Pluralize
When a compound consists of a noun followed by an adjective (or a title acting like one, such as șef or adjunct), both words take a plural ending. Because the first word is the head noun, the definite article attaches there (e.g., redactorii-șefi, not redactori-șefii).
| The editors-in-chief are usually very busy. | Redactorii-șefi sunt de obicei foarte ocupați. |
| Deputy directors often check these documents. | Directorii-adjuncți verifică adesea aceste documente. |
| The head nurses take care of the patients. | Asistentele-șefe au grijă de pacienți. |
Noun + Invariable Noun: Only the First Word Pluralizes
If the second half of a compound is a noun acting as a fixed concept or metaphor (like cheie or minune), it stays exactly the same. Only the first word pluralizes and takes the article.
| They are the key people in our project. | Ei sunt oamenii-cheie din proiectul nostru. |
| These child prodigies learn very fast. | Acești copii-minune învață foarte repede. |
Adverb + Noun: Only the Second Word Pluralizes
If the first word is an adverb (like liber or rău), it is invariable. Only the second word takes the plural endings and the definite article.
| Freelancers have a flexible schedule. | Liber-profesioniștii au un program flexibil. |
| The bad payers will pay a penalty. | Rău-platnicii o să plătească o penalitate. |
