Definitions
1.nounAn animal of the Amphibia; any four-legged vertebrate that does not have amniotic eggs, living both on land and in water.
2.nounA vehicle which can operate on land and water. See Wikipedia article on "Amphibious aircraft"
3.adjectiveOf or relating to the class Amphibia.
4.adjectiveCapable of operating on both land and water amphibious.
5.adjectiveHaving two natures.