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

Next, the researchers plan to expand their studies to other animal groups, including amphibians and fish, and to dig deeper into the biological mechanisms that generate the infraslow rhythm. —Rupendra Brahambhatt, Interesting Engineering, 24 Jan. 2026

There are only approximately 144 amphibian species that can tolerate very brief exposure to saltwater; this makes the crab-eating frog the most salt-tolerant amphibian known to science. —Scott Travers, Forbes.com, 22 Jan. 2026

The same doesn't apply to any amphibians who might want to join her in the night, however. —Phil Boucher, PEOPLE, 16 Jan. 2026

According to the researchers, the Atlantic Forest supports about 270 mammalian species, 850 kinds of birds and about 570 reptiles and amphibians. —Jackie Flynn Mogensen, Scientific American, 15 Jan. 2026

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

1654, 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