also faeces, c.1400, "dregs," from Latin faeces "sediment, dregs," plural of faex (genitive faecis) "grounds, sediment, lees, dregs," of unknown origin. Specific sense of "human excrement" is from 1630s.
feces fe·ces (fē'sēz)
The matter that is discharged from the bowel during defecation; excrement. Also called stercus.