How many letters does the top answer for “a short jacket worn by men and by women. ld. lutton.” have?

The most common answer is spencer (7 letters).

Crossword clue: a short jacket worn by men and by women. ld. lutton.

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

spencer 7 letters web-def

English philosopher and sociologist who applied the theory of natural selection to human societies (1820-1903)