石

also 斛

1. noun koku; traditional unit of volume, approx. 180.4 litres
2. measure of a Japanese-style boat's loading capacity (approx. 278.26 liters)

いし

1. noun stone; rock; pebble
2. jewel; precious stone
3. flint (in a lighter)
4. (round) game piece; stone (in go, etc.); disc (in Othello)
5. medicine stone (in the bladder, kidney etc.); calculus

せき

1. counter counter for jewels in a watch
2. counter for transistors, diodes, etc. in an electronic product