mammoth jack

[ mam-uhth jak ]

noun

1. Informal. a notably large male donkey.
2. any of various large donkey breeds, including the American mammoth donkey, a landrace bred for strength from several donkey breeds brought into America in the 18th century.

Word History and Origins

Origin of mammoth jack¹

First recorded in 1835–40; jack ¹( def ) (in the sense “male donkey, jackass”)