石いし

noun

stone; rock; pebble

General term for a stone or rock of any size, from a pebble to a boulder.

• 道みちに大おおきな石いしが落おちていた。

  A big stone was lying on the road.

• 子こ供どもが川かわで石いしを投なげて遊あそんでいる。

  The children are playing by throwing stones into the river.

noun

jewel; precious stone

Refers to gemstones, often used in compounds like 宝石 (ほうせき). Standalone use is less common but understood.

• 指ゆび輪わにきれいな石いしがついている。

  The ring has a beautiful stone set in it.

noun

flint (in a lighter)

Specifically the flint in a cigarette lighter or similar sparking device.

• ライターの石いしがなくなった。

  The lighter's flint has run out.

noun

game piece; stone (in go); disc (in Othello)

A round piece used in board games, especially go stones or Othello discs.

• 碁ご盤ばんの上うえに白しろと黒くろの石いしを置おく。

  Place white and black stones on the go board.

noun

stone (in the body); calculus

Medical term for a calculus, such as a kidney stone or bladder stone.

• 腎じん臓ぞうに石いしができてしまった。

  I developed a stone in my kidney.