Noun

knee (plural knees)

1. In humans, the joint in the middle part of the leg.

   Jessica was wearing shorts, so she skinned her exposed knees when she fell.

2. (anatomy) The joint, or region of the joint, between the thigh and leg.
3. (anatomy) In the horse and allied animals, the carpal joint, corresponding to the wrist in humans.
4. (shipbuilding) A piece of timber or metal formed with an angle somewhat in the shape of the human knee when bent.
   • 1980, Richard W. Unger, The Ship in the Medieval Economy 600-1600, page 41

     Deck beams were supported by hanging knees, triangular pieces of wood typically found underneath the timbers they are designed to support, but in this case found above them.

5. (archaic)An act of kneeling, especially to show respect or courtesy.

   Give them title, knee, and approbation. Shak.

   To make a knee.

6. Any knee-shaped item or sharp angle in a line, "the knee of a graph", an inflection point
7. A blow made with the knee; a kneeing

Derived terms

• down on one's knees
• kneecap
• kneejerk
• kneel
• kneepan
• knees-up

The knee joint joins the thigh with the leg and consists of two articulations: one between the femur and tibia, and one between the femur and patella. It is the largest joint in the human body and is very complicated. The knee is a mobile trocho-ginglymus (i.e. a pivotal hinge joint), which permits flexion and extension as well as a slight medial and lateral rotation. Since in humans the knee supports nearly the whole weight of the body, it is the joint most vulnerable to both acute injury and the development of osteoarthritis.

It is often grouped into tibiofemoral and patellofemoral components. (The fibular collateral ligament is often considered with tibiofemoral components.)