How many letters does the top answer for “having but one brood in a season.” have?

The most common answer is monogoneutic (12 letters).

Crossword clue: having but one brood in a season.

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

monogoneutic 12 letters web-def

Having but one brood in a season.

having but one branch. 50% similar → uniramous

having but one cilium. 50% similar → monociliated

having but one ray. 50% similar → uniradiated