An alligator, or colloquially gator, is a large reptile in the genus Alligator of the family Alligatoridae of the order Crocodilia. The two extant species are the American alligator (A. mississippiensis) and the Chinese alligator (A. sinensis). Additionally, several extinct species of alligator are known from fossil remains. Alligators first appeared during the late Eocene epoch about 37 million years ago.
The name "alligator" is likely an anglicized form of el lagarto, the Spanish term for "the lizard", which early Spanish explorers and settlers in Florida called the alligator. Early English spellings of the name included allagarta and alagarto.