Etymology

Noun

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. The joint, or region of the joint, between the thigh and leg.
3. In the horse and allied animals, the carpal joint, corresponding to the wrist in humans.
4. 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. 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

Verb

1. to kneel to
   • 1605: I could as well be brought / To knee his throne and, squire-like, pension beg / To keep base life afoot. — William Shakespeare, King Lear II.ii
2. poke or strike with the knee