Amphibian

As a noun, an animal like a frog, toad, or salamander that can live both in water and on land. As an adjective, it describes something that operates in two different environments, such as an amphibian vehicle.

From Greek *amphibios* (“living a double life”), from *amphi-* (“both, on both sides”) and *bios* (“life”). The Latin form *amphibium* led to English “amphibian.”