Definitions
1.nounA bone that forms a knuckle in the human hand, in an animal's paw or any bone that forms a similar bump.
2.nounSuch a bone once used in children's games of chance.
3.nounA die.
4.nounA children's game, originally played with the knucklebones of sheep, in which small objects are picked up, moved, thrown, and caught according to various rules.