How many letters does the top answer for “relating to a comet.” have?

The most common answer is cometic (7 letters).

Crossword clue: relating to a comet.

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

cometic 7 letters web-def

of or relating to or resembling a comet

of or relating to or resembling a comet 67% similar → cometary, cometic

of or relating to words 50% similar → lexical

the department of astronomy relating to comets. 50% similar → cometology