How many letters does the top answer for “one of the entozoa.” have?

The most common answer is entozooen (9 letters).

Crossword clue: one of the entozoa.

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

entozooen 9 letters web-def

One of the Entozoa.

entozoon 8 letters web-def

any of various parasites that live in the internal organs of animals (especially intestinal worms)

one versed in the science of the entozoa. 50% similar → entozooelogist, entozoologist