cloaca

noun

Etymology: Borrowed from Latin cloāca (“sewer”), related to cluō (“cleanse; purge”), but the derivation is uncertain.

1. A sewer.

   “The Thames, polluted with the filthy effusions of the cloacae.”

   “[…] that tremendous cloaca of Pauperism […]”

2. The opening in reptiles, amphibians and birds, as well as elasmobranchians, lobe-finned fishes, and monotreme mammals, which serves as the common outlet for the urogenital ducts and rectum.

   “In birds the rectum, at the termination of its canal, forms an oval or elongated pouch […] and then expands into a cavity, which has been named cloaca.”

3. An outhouse or lavatory.

   “To every house […] a cloaca.”

   “Only think of that cloaca being supplied daily with such dainty bibliographical treasures!”

4. A duct through which gangrenous material escapes a body.

   “Across this shell [sc. of bone] small holes are eaten, by which the matter escapes, and which are called cloacae (Weidmann).”

5. Structure in the embryo during the development of the reproductive and urinary systems.