円えん石せき

noun

round stone; pebble; boulder; cobblestone

General term for a naturally rounded stone of any size, from small pebbles to large boulders. Often used in contexts like gardening, geology, or describing river stones.

• 庭にわに円えん石せきを敷しき詰つめた。

  I paved the garden with round stones.

• 川原かわらで美うつくしい円えん石せきを見みつけた。

  I found a beautiful round stone by the river.

noun

coccolith

Geological term for the microscopic calcareous plates that form the shells of coccolithophores. Rare outside scientific contexts.

See also: ココリス

• 円えん石せきはコッコリソフォアの殻からを構こう成せいする微び細さいな構こう造ぞう物ぶつである。

  Coccoliths are microscopic structures that make up the shells of coccolithophores.