How many letters does the top answer for “a word consisting of four syllables; a quadrisyllable.” have?

The most common answer is tetrasyllable (13 letters).

Crossword clue: a word consisting of four syllables; a quadrisyllable.

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

tetrasyllable 13 letters web-def

A word consisting of four syllables; a quadrisyllable.

a foot consisting of four short syllables. 50% similar → proceleusmatic

a word consisting of four syllables. de quincey. 50% similar → quadrisyllable

consisting of, or having, four syllables; quadrisyllabic. 50% similar → tetrasyllabic, tetrasyllabical