acetabulum
Concise Oxford English Dictionary © 2008 Oxford University Press:
acetabulum /ˌasɪˈtabjʊləm/
▶noun (pl. acetabula /-lə/)
- 1 Anatomy the socket of the hip bone, into which the head of the femur fits.
- 2 Zoology a sucker or other cup-shaped structure.
– origin ME (denoting a vinegar cup): from L., from acetum ‘vinegar’ + -abulum, denoting a container.
'acetabulum' also found in these Oxford entries:

