noun
General term for a stone or rock of any size, from a pebble to a boulder.
道に大きな石が落ちていた。
A big stone was lying on the road.
子供が川で石を
The children are playing by throwing stones into the river.
noun
Refers to gemstones, often used in compounds like 宝石 (ほうせき). Standalone use is less common but understood.
指輪にきれいな石がついている。
The ring has a beautiful stone set in it.
noun
Specifically the flint in a cigarette lighter or similar sparking device.
ライターの石がなくなった。
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.
碁盤の上に白と黒の石を置く。
Place white and black stones on the go board.
noun
Medical term for a calculus, such as a kidney stone or bladder stone.
腎臓に石ができてしまった。
I developed a stone in my kidney.