How many letters does the top answer for “having a margin or fringe of hairlike projections” have?

The most common answer is ciliate (7 letters).

Crossword clue: having a margin or fringe of hairlike projections

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

ciliate 7 letters wn-def

a protozoan with a microscopic appendage extending from the surface of the cell

ciliated 8 letters wn-def

having a margin or fringe of hairlike projections

having toothlike projections in the margin 50% similar → dentate