Source : Webster's Revised Unabridged Dictionary (1913)

Diprotodon \Di*pro"to*don\, n. [Gr. di- = di`s- twice + ? first
   + ?, ?, tooth.] (Paleon.)
   An extinct Quaternary marsupial from Australia, about as
   large as the hippopotamus; -- so named because of its two
   large front teeth. See Illustration in Appendix.