The day immediately before today; one day ago. / (figuratively) The past, often in terms of being outdated.

On the day before today. / (informal) As soon as possible.

(poetic) Past years; time gone by; yore. / (rare) Last year.

(informal, chiefly in the negative) To be new, naive, innocent, inexperienced, or easily deceived.

(archaic) Last night.

(archaic) A preceding night.

plural of yesteryear

(archaic) Yesterday evening.

(During) yesterday evening.

plural of yesterday.