"subservient, subordinate, serving as an aid," 1660s, from Latin ancillaris "relating to maidservants," from ancilla "handmaid," fem. diminutive of anculus "servant," literally "he who bustles about," from root of ambi- "around" (from PIE root *ambhi- "around") + PIE *kwol-o-, from root *kwel- (1) "revolve, move round."
