How many letters does the top answer for “another word for thunder” have?

The most common answer is boom (4 letters).

Crossword clue: another word for thunder

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

boom 4 letters gen-syn

make a resonant sound, like artillery

roar 4 letters gen-syn

make a loud noise, as of wind, water, or vehicles

roaring 7 letters gen-syn

a deep prolonged loud noise

another word for about 50% similar → approximately, roughly, some

another word for terms 50% similar → footing

another word for under 50% similar → nether

another word for word 50% similar → phrase