|an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle.|
|a calculus or concretion found in the stomach or intestines of certain animals, esp. ruminants, formerly reputed to be an effective remedy for poison.|
|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|
|4.||another word for amphibious|
|5.||of, relating to, or belonging to the class Amphibia|
|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.