feces n.

1570s, "to purify, clarify, clear from dregs or impurities," from Latin defaecatus, past participle of defaecare "cleanse from dregs, purify," from the phrase de faece "from dregs" (see de- + feces). Figurative sense "purge of extraneous matter" is from 1620s. Excretory sense "void feces from the bowels" is by 1849 in medical writing, probably from French. Related: Defecated; defecating.

1640s, "purification of the mind or soul" (figurative); 1650s, "act or process of separating from lees or dregs, a cleansing from impurities," from Late Latin defecationem (nominative deficatio), noun of action from past-participle stem of Latin defaecare "cleanse from dregs, purify," from the phrase de faece "from dregs" (see de- + feces). Meaning "act of evacuating the bowels" is from 1830. An Old English word for "bowel movement" was arse-gang literally "arse-going."