nostra

Nostra is the feminine singular form of the Italian possessive determiner meaning "our" or "ours." It accompanies feminine nouns, as Italian adjectives and determiners agree with the noun they modify. The corresponding forms are: nostro (masculine singular), nostra (feminine singular), nostri (masculine plural), and nostre (feminine plural). Examples include la nostra casa and le nostre idee.

Etymology: from Latin 'noster' meaning "our." In Latin, 'nostra' is the feminine singular form used before feminine nouns; for example, nostra aetate means "in our age." The word reflects the same possessive root across languages and historical periods.

Notable uses include La Cosa Nostra, the widely known name for the Italian-American Mafia, literally "our thing." Another prominent usage is Nostra Aetate, the Vatican II declaration on the relation of the Church to non-Christian religions, where 'nostra' functions as the feminine form of the possessive pronoun in Latin.

In modern Italian, nostra is commonly used in everyday speech to indicate possession by a group including the speaker, as in la nostra famiglia or le nostre tradizioni. Its usage is widespread in both private conversation and formal writing, and it appears in various personal, cultural, and institutional phrases.