Definition of "Thunder" :

noun: street names for heroin

noun: a deep prolonged loud noise

noun: a booming or crashing noise caused by air expanding along the path of a bolt of lightning

verb: utter words loudly and forcefully

verb: to make or produce a loud noise

"The river thundered below."

verb: move fast, noisily, and heavily

"The bus thundered down the road."

verb: be the case that thunder is being heard

"Whenever it thunders, my dog crawls under the bed."