How many letters does the top answer for “the british smooth sole, or scaldfish (psetta arnoglossa).” have?

The most common answer is megrim (6 letters).

Crossword clue: the british smooth sole, or scaldfish (psetta arnoglossa).

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

megrim 6 letters web-def

a severe recurring vascular headache; occurs more frequently in women than men