thunderegg

Etymology

From thunder + egg.

thunderegg means A roughly spherical, nodule-like geological structure, similar to a geode, that is formed within a rhyolitic lava flow. Lexicurio rates it Sui generis — a strength score of 89 out of 100.

noun

A roughly spherical, nodule-like geological structure, similar to a geode, that is formed within a rhyolitic lava flow.