Chambers's Twentieth Century Dictionary…
“ Knuckle, nuk′l, n. projecting joint of the fingers; (cook.) the knee-joint of a calf or pig.—v.i. to bend the fingers: to touch the forehead as a mark of respect: to yield.—v.t. (rare) to touch with the knuckle.—ns. Knuck′le-bones, a game (called also Dibs) ; Knuck′le-bow, the curved part of a sword-guard that covers the fingers; Knuck′le-dust′er, a kind of modern cestus, devised as a protection against garrotters ”
