What does cloaca mean?
A cloaca is the single terminal cavity through which the intestinal, urinary, and reproductive tracts discharge in birds, reptiles, amphibians, and monotremes — animals that, unlike most mammals, have no separate openings for these systems. In ornithology and herpetology the term is routine and neutral: researchers examine the cloaca to sex birds, study mating, or analyze waste. The word also has an older, figurative sense meaning a sewer or foul drain, inherited from ancient Rome, whose great main sewer was called the Cloaca Maxima, portions of which still function today. This extended use carries unpleasant connotations of filth and corruption and appears mainly in literary or historical writing. Derived forms include the adjective 'cloacal', as in 'the cloacal opening'. For anyone reading about animal anatomy or Roman engineering, 'cloaca' is the precise, authoritative term.
The common cavity at the end of the digestive tract in birds, reptiles, amphibians, and monotremes, into which the intestinal, urinary, and reproductive tracts open.
"The physician examined the parrot's cloaca for signs of infection."
Standard technical vocabulary in zoology, ornithology, and veterinary medicine.
A sewer or foul drain; sometimes used figuratively for a place regarded as filthy or morally corrupting.
"Tour guides point out where the Cloaca Maxima empties into the Tiber."
Usually capitalized when referring to named Roman structures such as the Cloaca Maxima.
The plural follows the Latin first-declension pattern; it is uncommon outside technical contexts.
"Both specimens showed abnormalities in their cloacae."
In ancient Rome, the Cloaca Maxima — 'the greatest sewer' — still drains parts of Rome today, over 2,500 years after it was built.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of cloaca
Cloaca comes directly from Latin cloaca, meaning 'sewer' or 'drain', from the verb cluere, 'to cleanse or purge', which shares an Indo-European root with Greek klyzein, 'to wash'. That Greek line also gives us 'cataclysm', literally a washing-over, making the two words distant relatives. The word entered English as a learned borrowing, first applied to sewers and later adopted by naturalists as the anatomical term for the shared excretory chamber.
Related word forms
How cloaca is actually used
The anatomical sense is technical and neutral, appearing chiefly in biology, veterinary medicine, and ornithology. The figurative sense referring to a sewer or place of corruption carries strongly negative connotations and is largely literary or historical; it appears most often capitalized when naming Roman structures such as the Cloaca Maxima. The plural is the Latinate 'cloacae' (pronounced /kləʊˈeɪsiː/), though the word is rarely needed in the plural.