1. A being that lives either in water or on land, or is equally at home in either element.
2. A class of quadruped vertebrates containing frogs, newts, salamanders, toads, caecilians, and many fossil groups.

They have skin glandular without epidermal scales, feathers, or hairs with a tail present primitively but lost in some groups. They have limbs or girdles reduced or absent in some forms. Eggs are anamniotic, primitively laid in water with external fertilization. Tadpole larvae posses gills and open gill slits. Ovoviviparity and viviparity are exhibited by some species and these vertebrates contain a single extant subclass called Lissamphibia.

A class of quadruped vertebrates containing frogs, newts, salamanders, toads, and many fossil groups.