Hip

HIP (Heb שׁוֹק, H8797, leg, limb, thigh). This particular Heb. word is used only once (Judges 15:8) where Samson smote the Philistines “hip and thigh with great slaughter,” but the thigh can be taken to be the whole portion of the lower extremity above the knee. It is the symbol of strength as in Behemoth (Job 40:15) and in Jacob (Gen 32:32). Jacob’s thigh was smitten to reduce his feeling of self-sufficiency and to make him lean upon the Strong One, hence his name was changed to Israel. The loins also may include the hip. The priest’s breeches covered from the loins to the thigh (Exod 28:42), the sword was worn on the thigh or side (32:27), and the thigh was struck in a gesture of grief. The loins are a euphemism for reproductive organs, “nations out of his loins” (Gen 46:26 KJV). A priest predicted that the thigh would fall away in an unfaithful wife.

International Standard Bible Encyclopedia (1915)

Samson smote the Philistines "hip and thigh" (Hebrew "leg upon thigh"), which was indicative of "a great slaughter" (Jud 15:8), the bodies being hewed in pieces with such violence that they lay in bloody confusion, their limbs piled up on one another in great heaps.