How many letters does the top answer for “of or relating to locomotion” have?

The most common answer is locomotive (10 letters).

Crossword clue: of or relating to locomotion

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

locomotive 10 letters wn-def

a wheeled vehicle consisting of a self-propelled engine that is used to draw trains along railway tracks

locomotor 9 letters wn-def

of or relating to locomotion

of or relating to words 50% similar → lexical