amphibian

noun

am·​phib·​i·​an am-ˈfi-bē-ən 

1

: an amphibious organism

especially : any of a class (Amphibia) of cold-blooded vertebrates (such as frogs, toads, or salamanders) intermediate in many characters between fish and reptiles and having gilled aquatic larvae and air-breathing adults

Unlike reptiles, most amphibians possess a smooth, moist skin and lay their shell-less eggs in water or wet places.

—Jeffrey P. Cohn

2

: an amphibious vehicle

especially : an airplane designed to take off from and land on either land or water

amphibian adjective

Examples of amphibian in a Sentence

Recent Examples on the Web

Adult alligators eat fish, snakes, turtles, small mammals and birds, while juvenile alligators primarily eat insects, amphibians, small fish and other invertebrates, the commission says. —Greta Cross, USA TODAY, 21 Feb. 2025

These receptor systems, first characterized in mammals, have since been identified across a variety of vertebrates, including birds, amphibians, and even sharks. —Melissa Cristina Marquez, Forbes, 12 Jan. 2025

Even more unexpected, out of the hundreds of species documented, 27 were new to science, including four new mammals, eight fish, three amphibians, and ten butterfly species. —Kelli Bender, People.com, 25 Dec. 2024

But after reconstructing the bones, Lovelace noticed indications of a lateral line organ, part of the sensory apparatus that amphibians use to react to changes in their aquatic environment. —Eli Wizevich, Smithsonian Magazine, 11 Dec. 2024

Word History

Etymology

New Latin Amphibia, taxon including frogs and salamanders (from neuter plural of amphibius amphibious) + -an entry 1

Note: As a taxon Amphibia was used as a class name already by linnaeus (Systema naturae, 10. editio, 1758, p. 196 et passim), but in a sense that included both amphibians and some reptiles. Limitation of the taxon to approximately its current meaning dates from Thomas Gray's "A Synopsis of the Genera of Reptiles and Amphibia" (Annals of Philosophy, new series vol. 10, July-December, 1825, pp.193-217) according to Darrel R. Frost, et al., "The Amphibian Tree of Life," Bulletin of the American Museum of Natural History, No. 297 (2006), p. 355. The use of both English amphibian and Latin amphibius with varying gender and number to refer to animals living on both land and sea (and in figurative senses) can be found much earlier.

First Known Use

1749, in the meaning defined at sense 1

Rhymes for amphibian

• caribbean
• libyan

Kids Definition

amphibian

noun

am·​phib·​i·​an am-ˈfib-ē-ən 

1

: any organism that is able to live both on land and in water

especially : any of a class of cold-blooded vertebrate animals (as frogs and salamanders) that in many respects are between fishes and reptiles

2

: an airplane designed to take off from and land on either land or water

amphibian adjective