MASTODON
mastodon, mastodont
(noun) extinct elephant-like mammal that flourished worldwide from Miocene through Pleistocene times; differ from mammoths in the form of the molar teeth
Source: WordNet® 3.1
Noun
Mastodon (plural Mastodons)
A nickname for both the 4-8-0 and (though incorrectly) the 4-10-0 train configurations.
Etymology
Noun
mastodon (plural mastodons)
Extinct elephant-like mammal of the genus Mammut that flourished worldwide from Miocene through Pleistocene times; differs from elephants and mammoths in the form of the molar teeth.
Source: Wiktionary
Mas"to*don, n. Etym: [Gr. (Paleon.)
Definition: An extinct genus of mammals closely allied to the elephant, but
having less complex molar teeth, and often a pair of lower, as well
as upper, tusks, which are incisor teeth. The species were mostly
larger than elephants, and their romains occur in nearly all parts of
the world in deposits ranging from Miocene to late Quaternary time.
Source: Webster’s Unabridged Dictionary 1913 Edition