Cloaca: A common passageway for feces, urine and reproduction.
At one point in the development of the human embryo, there is a cloaca. It is the far end of a structure called the hindgut. This structure then divides to form a rectum, a bladder, and genitalia.
The presence of a cloaca is normal in many adult animals (birds, reptiles, amphibians, some fish, and even a few mammals). However, the persistence of a persistent cloaca in a person is a birth defect (a congenital malformation).
Cloaca is the Latin word for drain or sewer.