thunder

Concise Oxford English Dictionary © 2008 Oxford University Press:
thunder/ˈθʌndə(r)/

▶noun

• 1 a loud rumbling or crashing noise heard after a lightning flash due to the expansion of rapidly heated air.

• 2 a resounding loud, deep noise.

▶verb

• 1 (it thunders, it is thundering, etc.) thunder sounds.

• 2 move heavily and forcefully.

• 3 speak loudly, angrily, and forcefully, especially to protest: he thundered against the evils of the age.

– derivatives
thunderer noun,
thundery adjective.

– origin OE thunor (n.), thunrian (v.), of Gmc origin.