n.
Pronunciation: ' th ə n-d ə r
Function: noun
Etymology: Middle English thoner, thunder, from Old English thunor; akin to Old High German thonar thunder, Latin tonare to thunder
Date: before 12th century
1 : the sound that follows a flash of lightning and is caused by sudden expansion of the air in the path of the electrical discharge
2 : a loud utterance or threat
3 : BANG , RUMBLE <the thunder of big guns>