caduceus /kədo̅o̅″sē·əs/ [L; Gk, karykeion, herald] , the wand of the god Hermes or Mercury, used as the symbol for the U.S. Army Medical Corps. It is represented as a staff with two serpents coiled around it and is often confused with the staff of Æsculapius, a rod with one snake entwined about it.