1640s, "pertaining to sympathy," from Modern Latin sympatheticus, from Greek sympathetikos, from sympathein, from sympathes "having a fellow feeling, affected by like feelings" (see sympathy). Meaning "having fellow feeling" is recorded from 1718. In anatomical sense, the word is attested from 1769, from Modern Latin (nervus) sympathicus, coined by Jacques-Benigne Winslow (1669-1760), Danish anatomist living in Paris. Related: Sympathetically.
sympathetic sym·pa·thet·ic (sĭm'pə-thět'ĭk)
Of, relating to, or acting on the sympathetic nervous system.