To defecate is defined as to have a bowel movement.(verb)
When you expel feces, this is an example of a time when you defecate.
See defecate in Webster's New World College Dictionary
Origin: < L defaecatus, pp. of defaecare, to cleanse from dregs, strain < de-, from + faex (gen. faecis), grounds, dregs
See defecate in American Heritage Dictionary 4
verb def·e·cat·ed, def·e·cat·ing, def·e·cates verb, intransitive
Origin: Latin dēfaecāre, to clean the dregs from
Origin: : dē-, de-
Origin: + faex, faec-, dregs.
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