What does acetabula mean?
Acetabula are the two cup-shaped depressions in the pelvis that receive the rounded heads of the thigh bones, forming the ball-and-socket hip joints. The word is simply the plural of acetabulum, a Latin term originally denoting a small vessel for vinegar; anatomists adopted it because the hollow of the hip bone resembles such a cup. In contemporary English, acetabula appear almost exclusively in medical and scientific writing — orthopedic surgeons discuss fractures of the acetabula, radiologists evaluate their depth and coverage, and paleontologists use them to study posture in fossil vertebrates. A related historical sense refers to Roman liquid measures of roughly one-eighth of a pint. Because the term is inherently plural, writers must take care to pair it with plural verbs and pronouns, reserving the singular acetabulum for a single socket.
The cup-shaped sockets of the pelvis that receive the heads of the femora to form the hip joints.
"Both acetabula showed signs of wear consistent with advanced osteoarthritis."
Always plural; the singular is acetabulum. Used almost exclusively in anatomy, medicine, and zoology.
Roman liquid measures, each equivalent to about one-eighth of a pint (roughly 68 millilitres).
"The recipe called for two acetabula of garum."
A historical/archaeological sense, rarely encountered outside discussions of ancient Roman measurement.
Acetabula is already the standard plural of acetabulum; it takes plural agreement with verbs and pronouns.
"The acetabula were examined for signs of developmental dysplasia."
The Romans named the hip socket after their little vinegar cup — the acetabulum — because the bone's hollow shape reminded them of it.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of acetabula
Acetabula derives from Latin acetabulum, meaning a small vinegar cup or saucer, itself formed from acetum ('vinegar') plus the diminutive suffix -bulum. Roman writers used the word both for the drinking vessel and for a small unit of liquid measure. Anatomists in the post-classical period borrowed the Latin term for the hip socket because of its distinctive cup-like shape, and English medical texts have used acetabulum/acetabula since at least the early modern era. Cognates sharing the vinegar root include acetic acid and acetate.
Related word forms
How acetabula is actually used
Strictly technical and anatomical in modern usage; encountered mainly in medical, surgical, and paleontological contexts. The word is always plural when spelled 'acetabula' — the singular is 'acetabulum'. Adjectival form is 'acetabular'.
Easily confused with acetabula
Acetabulum is the singular form referring to one hip socket, while acetabula is its plural, referring to two or more.