a word common to Indo-European languages, cf. Ger. Knie, Fr. genou, Span. hinojo, Lat. genu, Gr. ybvv, Sansk. janu), in human anatomy, the articulation of the upper and lower parts of the leg, the joint between the femur and the tibia (see Joints). The word is also used of articulation resembling the knee-joint in shape or position in other animals; it thus is applied to the carpal articulation of the fore leg of a. horse, answering to the ankle in man, or to the tarsal articulation. or heel of a bird's foot.