Defecation

n. bowel movement

Defecation is the act or process by which organisms eliminate solid or semisolid waste material (feces) from the digestive tract via the anus. Humans expel feces anywhere from a few times daily to a few times weekly; sloths can go a week without expelling. Waves of muscular contraction known as peristalsis in the walls of the colon move fecal matter through the digestive tract towards the rectum. Undigested food may also be expelled this way; this process is called egestion.
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Defecation /def·e·ca·tion/ 1. the evacuation of fecal matter from the rectum. 2. the removal of impurities, such as chemically. [more]Defecation - Community and Resources

Noun
1. the elimination of fecal waste through the anus
(synonym) laxation, shitting
(hypernym) elimination, evacuation, excretion, excreting, voiding
(hyponym) bowel movement, movement, bm
(derivation) stool, defecate, shit, take a shit, take a crap, ca-ca, crap, make

n. defecation