Plural of 'acetabulum'; the cup-shaped socket bones in the pelvis that receive the head of the thighbone, or similar cup-shaped structures in anatomy.
From Latin 'acetabulum' (vinegar cup), literally from 'acetum' (vinegar) + 'abulum' (small holder). Romans named this socket bone after the shape of small vinegar dishes they used, because the bone's cavity resembled those shallow cups.
The Romans looked at this bone socket and thought 'that looks like our vinegar cup'—so they named the hip joint after tableware! It's wild that we still use this 2,000-year-old name, and it reveals how ancient people noticed shapes in unexpected places.
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