9 letters · 11 points in Scrabble
adjective (of speed) having or caused by speed approximately equal to that of sound in air at sea level
originEtymology tree English tran- Proto-Indo-European *swenh₂- Proto-Indo-European *swónh₂os Latin sonus Proto-Indo-European *-ikos Proto-Italic *-ikos Latin -icuslbor. Old French -iquebor. Middle English -ik English -ic English sonic English transonic From tran- + sonic.
Etymology from Wiktionary, CC BY-SA 3.0