How many letters does the top answer for “the evening of yesterday; the evening last past.” have?

The most common answer is yestereve (9 letters).

Crossword clue: the evening of yesterday; the evening last past.

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

yestereve 9 letters web-def

The evening of yesterday; the evening last past.

yesterevening 13 letters web-def

The evening of yesterday; the evening last past.

the noon of yesterday; the noon last past. 60% similar → yesternoon