Etymology: Middle English knokylle bone, from knokylle, knokel knuckle + bone, bon bone
1.
a. : one of the bones forming a knuckle of a human finger
b. : a long bone with a knobbed end (as a femur or humerus); also : the knob of such a bone — now used only of animals
2.
a. : the tetrahedral metacarpal or metatarsal bone of a sheep; especially : such a bone marked on its surfaces and used in ancient times in gaming and divination usually through being tossed like one of a pair of dice
b. knucklebones plural but singular in construction : a game played with such marked bones or with small metal objects resembling such bones; especially : jacks
Useful english dictionary. 2012.