thunder, thunderous, thundery, thunderous, thunderously, thunderousness 1. A booming or crashing noise caused by air expanding along the path of a bolt of lightning. 2. Noise resembling thunder; such as, a loud deep rumbling noise resembling thunder. 3. A manifestation of someone's anger in an explosion of strong words. 4. Etymology: from Middle... Found on http://www.wordinfo.info/words/index/info/view_unit/2159/