THUNDER

I. noun Etymology: Middle English thoner, ~, from Old English thunor; akin to Old High German thonar ~, Latin tonare to ~ Date: before 12th century the sound that follows a flash of lightning and is caused by sudden expansion of the air in the path of the electrical discharge, a loud utterance or threat, bang , rumble , II. verb (~ed; ~ing) Date: before 12th century intransitive verb 1. to produce ~, to give forth a sound that resembles ~ , roar , shout , transitive verb to utter loudly ; roar , to strike with a sound likened to ~, ~er noun