"small ball or round mass of medicine," c.1400, from Middle Dutch or Middle Low German pille and Middle French pile, all from Latin pilula "pill," literally "little ball," diminutive of pila "a ball, playing ball," said to be related to pilus "hair" if the original notion was "hairball." Figurative sense "something disagreeable that must be swallowed" is from 1540s; slang meaning "boring person" is recorded from 1871. The pill "contraceptive pill" is from 1957.

1736, "to dose on pills," from pill, n.. From 1882 as "to form into pills." Related: Pilled; pilling.