tri·phib·i·an I. \(ˈ)trī|fibēən\noun (-s) Etymology:tri- + -phibian (as in amphibian, n.) 1.: a person and especially a military commander who is triphibian 2.: a triphibian airplane II. adjective Etymology:tri- + -phibian (as in amphibian, adjective) 1. a.: adept at war alike on land, at sea, and in the air b.: designed for or equipped to operate from land, water, snow, or ice as well as in the air < a triphibian airplane > 2.: triphibious 1 < a triphibian military operation >