[am-fib-ee-uh
n] 
| 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. |
| am·phib·i·an (ām-fĭb'ē-ən) n.
[From New Latin Amphibia, class name, from Greek, neuter pl. of amphibios, amphibious : amphi-, amphi- + bios, life; see gwei- in Indo-European roots.] |
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.
| amphibian (ām-fĭb'ē-ən) Pronunciation Key
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. Our Living Language : 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. |