( sometimes initial capital letter ) the evening or the day before a holiday, church festival, or any date or event

Christmas Eve; the eve of an execution.

the period preceding or leading up to any event, crisis, etc.

on the eve of the American Revolution.

the evening.

noun

evening before , vigil , verge , brink , threshold , night , evening , dusk , eventide , gloaming , nightfall , twilight , sundown , sunset