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definitions

amphibian

[am-fib-ee-uh n]
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noun
  1. any cold-blooded vertebrate of the class Amphibia, comprising frogs and toads, newts and salamanders, and caecilians, the larvae being typically aquatic, breathing by gills, and the adults being typically semiterrestrial, breathing by lungs and through the moist, glandular skin.
  2. an amphibious plant.
  3. an airplane designed for taking off from and landing on both land and water.
  4. Also called amtrac. a flat-bottomed, armed, military vehicle, equipped with both tracks and a rudder, that can travel either on land or in water, used chiefly for landing assault troops.
adjective
  1. belonging or pertaining to the Amphibia.
  2. amphibious(def 2).

Origin of amphibian

1630–40; < Latin amphibi(a), neuter plural of amphibius (adj.) (see amphibious) + -an
Related formsnon·am·phib·i·an, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words for amphibians

toad, frog, salamander, hyla, proteus, caecilian, caudate, newt

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British Dictionary definitions for amphibians

amphibian

noun
  1. any cold-blooded vertebrate of the class Amphibia, typically living on land but breeding in water. Their aquatic larvae (tadpoles) undergo metamorphosis into the adult form. The class includes the newts and salamanders, frogs and toads, and caecilians
  2. a type of aircraft able to land and take off from both water and land
  3. any vehicle able to travel on both water and land
adjective
  1. another word for amphibious
  2. of, relating to, or belonging to the class Amphibia
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Word Origin and History for amphibians

amphibian

adj.

1630s, "having two modes of existence, of doubtful nature," from Greek amphibia, neuter plural of amphibios "living a double life," from amphi- "of both kinds" (see amphi-) + bios "life" (see bio-).

Formerly used by zoologists to describe all sorts of combined natures (including otters and seals), the biological sense "class of animals between fishes and reptiles that live both on land and in water" and the noun derivative both are first recorded 1835. Amphibia was used in this sense from c.1600 and has been a zoological classification since c.1819.

Online Etymology Dictionary, © 2010 Douglas Harper
amphibians in Science

amphibian

[ăm-fĭb′ē-ən]
  1. A cold-blooded, smooth-skinned vertebrate of the class Amphibia. Amphibians hatch as aquatic larvae with gills and, in most species, then undergo metamorphosis into four-legged terrestrial adults with lungs for breathing air. The eggs of amphibians are fertilized externally and lack an amnion. Amphibians evolved from lobe-finned fish during the late Devonian Period and include frogs, toads, newts, salamanders, and caecilians.
Word History: Amphibians, not quite fish and not quite reptiles, were the first vertebrates to live on land. These cold-blooded animals spend their larval stage in water, breathing through their gills. In adulthood they usually live on land, using their lungs to breath air. This double life is also at the root of their name, amphibian, which, like many scientific words, derives from Greek. The Greek prefix amphi- means “both,” or “double,” and the Greek word bios means “life.” Both these elements are widely used in English scientific terminology: bios, for example, is seen in such words as biology, antibiotic, and symbiotic.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
amphibians in Culture

amphibians

[(am-fib-ee-uhnz)]

Vertebrate animals, such as frogs, that live part of their life cycle in the water and the other part on land.

Note

Amphibian is also used to describe things such as vehicles that can operate both on land and in the water.

Note

Amphibians were the first land-dwelling animals to evolve.
The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.