How many letters does the top answer for “divided into four parts.” have?

The most common answer is quadripartite (13 letters).

Crossword clue: divided into four parts.

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

quadripartite 13 letters web-def

involving four parties

a subdivision into four parts. 50% similar → quadrisection

divided into a hundred parts. 50% similar → centifidous

divided into twelve parts. 50% similar → duodecimfid