Definition of mastodont in US English:

mastodont

noun

  • An extinct mammal of the order Proboscidea, related to the elephants and mammoths; especially one of the family Mammutidae (formerly Mastodontidae) which comprises the true mastodons.

Origin

Early 19th century; earliest use found in Thomas Jefferson (1743–1826), revolutionary politician and president of the United States of America. From French mastodonte from masto- + -odonte, with reference to the nipple-like tubercles present in pairs on the crowns of the molar teeth.

Pronunciation

mastodont

/ˈmastədɒnt/