What does capitulum mean?
Capitulum is the Latin word for 'little head', and it survives in English as a precise technical term with two main scientific uses. In botany, it denotes the distinctive inflorescence of the daisy family (Asteraceae): a flattened or dome-shaped receptacle densely packed with tiny, stalkless florets, which together masquerade as a single flower. What looks like one sunflower or one daisy bloom is in fact a capitulum made up of dozens or hundreds of individual flowers. In anatomy, a capitulum is a small, rounded, knob-like prominence at the end of a long bone — such as that of the humerus or radius — that fits into a corresponding hollow to allow smooth joint movement. The word belongs firmly to formal, scientific registers and is unfamiliar to most general readers, though its root is shared with everyday words like 'capital' and 'chapter'. The standard plural is 'capitula'.
nounA dense cluster of small stalkless flowers arranged on a flattened receptacle, characteristic of the daisy family (Asteraceae); in anatomy, a rounded knob-like head at the end of a bone that articulates with another bone.
- The characteristic inflorescence of the daisy family (Asteraceae): a compressed cluster of sessile flowers on a receptacle, superficially resembling a single flower.
- In anatomy, a small rounded articular prominence at the end of a long bone.
"Each sunflower head is not a single flower but a capitulum composed of hundreds of tiny florets."
"The botanist noted that each capitulum bore both ray and disc florets."
"The surgeon identified the capitulum of the radius on the X-ray."
The Latin plural is standard in both botanical and anatomical literature; an anglicized plural is not established.
"The specimen's capitula were examined under a dissecting microscope."
That sunflower on your windowsill isn't one flower at all — it's a capitulum, a whole city of hundreds of tiny flowers pretending to be one.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of capitulum
Capitulum comes directly from Latin, where it is the diminutive of caput, meaning 'head' — literally 'a little head'. The term was adopted into English scientific Latin, appearing in botanical and anatomical usage by around the late seventeenth century as naturalists systematized plant and skeletal terminology. It shares its root with a wide family of English words derived from caput, including 'capital', 'chapter', 'decapitate', and 'per capita', all of which preserve some notion of a 'head' — whether of a state, a book, a body, or a person.
Related word forms
How capitulum is actually used
Strictly technical vocabulary, used almost entirely in botany and anatomy; rarely encountered outside scientific writing. The Latin plural 'capitula' is standard in scholarly use.
Easily confused with capitulum
Both derive from Latin caput ('head'), but 'chapter' means a division of a book or a branch of an organization, while 'capitulum' is a technical term for a flower cluster or bony knob.