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