from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun A sewer or latrine.
  • noun The common cavity that serves as the opening for the intestinal, genital, and urinary tracts in many vertebrates, including amphibians, reptiles, birds, monotremes, and some fishes.
  • noun The posterior part of the intestinal tract in various invertebrates.

from The Century Dictionary.

  • noun An underground conduit for drainage; a common sewer: as, the cloaca maxima at Rome.
  • noun A sink; a privy.
  • noun [NL.] In zoology: In vertebrates, the enlarged termination of the rectum or lower bowel, forming a cavity originally in common with that of the allantois (in those animals which have an allantois) and permanently in common with the termination of the urogenital organs; the common chamber into which the intestine, ureters, sperm-ducts, and oviducts open, in sundry fishes, in reptiles and birds, and in the ornithodelphous mammals.
  • noun In invertebrates, the homologous or analogous and corresponding structure effecting sewerage of the body: as in sponges, the common cavity in which the interstitial canal-systems open; in holothurians, the respiratory tree (which see, under respiratory).
  • noun In entomology: A cavity found in many insects at the end of the abdomen, between the last dorsal and ventral segments, and receiving the extremity of the rectum. Also called the rectogenital chamber. The cæcum, or dilatation of the posterior end of the intestine.
  • noun In ascidians, the common central cavity into which open the atrial chambers of all the ascidiozooids of an ascidiarium.
  • noun [NL.] In pathology: In cases of necrosis, the opening in the sound bone which leads to the inclosed dead bone.
  • noun The union of rectum, bladder, and organs of generation in a common outlet: a malformation resulting from arrest of development.

from the GNU version of the Collaborative International Dictionary of English.

  • noun A sewer.
  • noun A privy.
  • noun (Anat.) The common chamber into which the intestinal, urinary, and generative canals discharge in birds, reptiles, amphibians, and many fishes.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun A sewer.
  • noun A privy.
  • noun anatomy The common duct in fish, reptiles, birds and some primitive mammals that serves as the anus as well as the genital opening.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • noun (zoology) the cavity (in birds, reptiles, amphibians, most fish, and monotremes but not mammals) at the end of the digestive tract into which the intestinal, genital, and urinary tracts open
  • noun a waste pipe that carries away sewage or surface water


from The American Heritage® Dictionary of the English Language, 4th Edition

[Latin cloāca, sewer, canal.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Latin cloāca ("sewer"), from cluō ("cleanse").



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  • The Roman, like the Englishman who follows in his footsteps, brought to every new shore on which he set his foot (on our shore he never set it) only his cloacal obsession. He gazed about him in his toga and he said: It is meet to be here. Let us construct a watercloset.

    Joyce, Ulysses, 7

    January 2, 2007

  • Leonard explores the intestines, where prickly creatures scurry, brushing against his legs. At last he sees daylight and exits through the cloaca.

    - William Steig, The Zabajaba Jungle

    October 5, 2008