This term refers to a vein, nerve, or sinew in the thigh region, traditionally identified as the sciatic nerve or the vein associated with the hip socket. Genesis 32:32 twice mentions 'the sinew of the thigh-vein' in explaining why Israelites do not eat this particular part of the animal—a practice rooted in Jacob's injury when he wrestled with the divine being at Peniel. The etymology is uncertain, but the term became the basis for an important dietary restriction in Jewish law. The word appears only in this etiological passage explaining the origin of the prohibition.