割り楔[warikusabi] split wedge
楔形[kusabigata] wedge-shape
楔形文字[kusabigatamoji] cuneiform (writing)
楔石[kusabiishi] keystone
楔状[ketsujou] wedge-shaped

楔状骨[ketsujoukotsu] cuneiform (bones)
楔子[kesshi] wedge
合いの楔[ainokusabi] wedge (for securing objects together)
氷楔[hyousetsu] ice wedge

圧し石[oshiishi] stone weight
一石[isseki] one game (of go)
一石二鳥[issekinichou] killing two birds with one stone
英国石油[eikokusekiyu] British Petroleum
下石[shitaishi] nether millstone

化粧石鹸[keshousekken] toilet soap
化石[kaseki] fossil
化石学[kasekigaku] paleontology
化石層[kasekisou] fossil bed
化石燃料[kasekinenryou] fossil fuel