knee

(noun) hinge joint in the human leg connecting the tibia and fibula with the femur and protected in front by the patella. Synonyms: knee joint, human knee, articulatio genus, genu.

(noun) joint between the femur and tibia in a quadruped; corresponds to the human knee. Synonyms: stifle.

(noun) the part of a trouser leg that provides the cloth covering for the knee.