'Self-acting' definitions:

Definition of 'self-acting'

From: WordNet
adjective
Designed to activate or move or regulate itself; "a self- activating sprinkler system" [syn: self-acting, self- activating, self-moving, self-regulating]

Definition of 'Self-acting'

From: GCIDE
  • Self-acting \Self`-act"ing\, a. Acting of or by one's self or by itself; -- said especially of a machine or mechanism which is made to perform of or for itself what is usually done by human agency; automatic; as, a self-acting feed apparatus; a self-acting mule; a self-acting press. [1913 Webster]