any of a class of amphibious organisms, esp frogs, toads, newts, or other members a frog, toad, newt, or other member of a class of cold-blooded vertebrates intermediate in many characteristics between fishes and reptiles and having gilled aquatic larvae and air-breathing adults: class Amphibia
an aeroplane, tank, etc adapted to operate on both land and water
amphibian adj
[Greek amphibion amphibious being, neuter of amphibios, literally ‘having a double life’, from amphi- + bios life]