1.
a. The joint between the thigh and the lower leg, formed by the articulation of the femur and the tibia and covered anteriorly by the patella.
b. The region of the leg that encloses and supports this joint.
2. An analogous joint or part of a leg of a quadruped vertebrate.
3. Something resembling the human knee, such as a bent piece of pipe.
4. The part of a garment, as of trousers, that covers the knee.
5. An abrupt woody projection arising from the roots of some swamp-growing trees: