Learn Hardcore Romanian: Biblioteca este închisă noaptea.

Because bibliotecă means “a library” or just the concept of a library (indefinite), while Biblioteca is the definite form, “the library.” In Romanian, the article is attached to the end of the noun.

Why do we use este instead of e?

Este is the full, formal form of the verb “to be” in the present tense. E is the colloquial contraction you’d hear in speech or informal writing. In standard or written Romanian, you’ll usually see este, though you could say Biblioteca e închisă noaptea in casual conversation.

Why does închisă end with -ă?

Închisă is the past participle of a închide (“to close”) used as an adjective. Romanian participles and adjectives agree in gender and number with the noun they describe. Biblioteca is feminine singular, so the adjective/participle also takes the feminine singular ending -ă. For a masculine noun you’d say închis, and for plural închise (fem.) or închiși (masc.).

What does noaptea literally mean and why is it used for “at night”?