{To knuckle to}.
(a) To submit to in a contest; to yield to. [Colloq.] See {To
knock under}, under {Knock}, v. i.
(b) To apply one's self vigorously or earnestly to; as, to
knuckle to work. [Colloq.]
2. The kneejoint, or middle joint, of either leg of a
quadruped, especially of a calf; -- formerly used of the
kneejoint of a human being.
With weary knuckles on thy brim she kneeled sadly
down. --Golding.
3. The joint of a plant. [Obs.] --Bacon.
4. (Mech.) The joining pars of a hinge through which the pin
or rivet passes; a knuckle joint.
5. (Shipbuilding) A convex portion of a vessel's figure where
a sudden change of shape occurs, as in a canal boat, where
a nearly vertical side joins a nearly flat bottom.
6. A contrivance, usually of brass or iron, and furnished
with points, worn to protect the hand, to add force to a
blow, and to disfigure the person struck; as, brass
knuckles; -- called also {knuckle duster}. [Slang.]
{Knuckle joint} (Mach.), a hinge joint, in which a projection
with an eye, on one piece, enters a jaw between two
corresponding projections with eyes, on another piece, and
is retained by a pin which passes through the eyes and
forms the pivot.
{Knuckle of veal} (Cookery), the lower part of a leg of veal,
from the line of the body to the knuckle.