jack
A coarse medieval coat of defence, especially one made of leather.
Other meanings
A name applied to a hypothetical or typical man.
A policeman or detective; Australia a military policeman.
Word history
From Middle French "jaque".
Where this comes from
This definition is adapted from “jack” on Wiktionary, by its contributors, published under CC BY-SA 4.0. This page is published under the same licence.