Do you know ghouls from goblins and ghosts?
1590s, from Latin caduceus, alteration of Doric Greek karykeion "herald's staff," from karyx (genitive karykos) "a herald," from PIE *karu-, from root *kar- "to praise loudly, extol" (cf. Sanskrit carkarti "mentions with praise," Old English hreð "fame, glory"). Token of a peaceful embassy; originally an olive branch. Especially the wand carried by Mercury, messenger of the gods, usually represented with two serpents twined round it.
caduceus ca·du·ce·us (kə-dōō'sē-əs, -shəs, -dyōō'-)
n. pl. ca·du·ce·i (-sē-ī')
A winged staff with two serpents twined around it, carried by Hermes.
An insignia modeled on Hermes' staff and used as the symbol of the medical profession.