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

The most common answer is furrow (6 letters).

Crossword clue: another word for groove

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

furrow 6 letters gen-syn

a long shallow trench in the ground (especially one made by a plow)

rut 3 letters gen-syn

a settled and monotonous routine that is hard to escape

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