Entry 3 senses · 2 variants Webster, 1913 claxon · IPA /klˈæksən/ n. v. 01 n. a kind of loud horn formerly used on motor vehicles. 1. a kind of loud horn formerly used on motor vehicles. Syn. klaxon. 02 v. to sound loudly; -- of car horns. 1. to sound loudly; -- of car horns. 2. to use the horn of a car. Syn. honk, blare, beep, toot, klaxon. — Syn. -- honk.