How many letters does the top answer for “relating to atmospheric pressure or indicated by a barometer” have?

The most common answer is barometric (10 letters).

Crossword clue: relating to atmospheric pressure or indicated by a barometer

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

barometric 10 letters wn-def

relating to atmospheric pressure or indicated by a barometer

barometrical 12 letters wn-def

relating to atmospheric pressure or indicated by a barometer