What is the meaning of Thunder?

The loud rumbling, cracking, or crashing sound caused by expansion of rapidly heated air around a lightning bolt.

A deep, rumbling noise resembling thunder.

An alarming or startling threat or denunciation.

The discharge of electricity; a thunderbolt.

(Can we verify this sense?) The spotlight.

Synonym of thunder word

To produce thunder; to sound, rattle, or roar, as a discharge of atmospheric electricity.

To make a noise like thunder.

To (make something) move very fast (with loud noise).

To say (something) with a loud, threatening voice.

To produce something with incredible power.

Alternative form of thonder

Source: wiktionary.org