the period between sunset and sunrise; evening; night; (classifier) used as a counter for nights or evenings

Negative adverb used before verbs, adjectives, and other adverbs to indicate negation; also used as a bound-form prefix to form terms with opposite meanings

(of a student or resident) to return to one's lodgings for the night, typically used in the phrase 夜不归宿 yè​bù​guī​sù