転てん石せき

noun

rolling stone; boulder

Refers to a stone that rolls or has rolled, or a large rounded rock. Often used in proverbs or geological contexts.

• 転てん石せき苔こけむさず。

  A rolling stone gathers no moss.

• 川かわ岸ぎしに大おおきな転てん石せきがいくつも転ころがっていた。

  Several large boulders were lying on the riverbank.