Word Study
autonomic
CIDE DICTIONARY
autonomic, a.
Having the power of self-government; autonomous. Hickok. [1913 Webster]
OXFORD DICTIONARY
autonomic, adj. esp. Physiol. functioning involuntarily.
Idiom
autonomic nervous system the part of the nervous system responsible for control of the bodily functions not consciously directed, e.g. heartbeat.
Etymology
AUTONOMY + -IC
For further exploring for "autonomic" in Webster Dictionary Online