knuckle joint
- any articulation, or point of movement, between two bones forming a knuckle
- a hinged joint formed by a knuckle on one part that fits between two knuckles on another part
See knuckle joint in American Heritage Dictionary 4
noun A hinged joint in which a pin fastens the ends of two rods, one of which has an eye that fits between the two perforated projections of the other.