It is the hole or cavity is inserted where the head of the femur in hip. Cavity, the coxal bone or the pelvis. Cavity or hole where the head of the femur is inserted. Bowl, glass or cup shaped.
((acetabulum - refers to 1) ancient measure for liquids that amounted to a quarter of the hemin - 2) cavity of one bone where fit other, mainly in the ischium, where comes the head of femur -
ACETABULUM: Bloodsucker of the tentacles, in the Octopus.