1A member of any of various former or current regiments and other divisions of the British Army who originally wore dark green uniforms, especially the King's Royal Rifle Corps or the Rifle Brigade; chiefly in plural; also occasionally attributive.
2Golf (with lower-case initials) a green sports coat awarded to the winner of the U.S. Masters Tournament.
Origin
Early 19th century.
Definition of Green Jacket in US English:
Green Jacket
noun
1A member of any of various former or current regiments and other divisions of the British Army who originally wore dark green uniforms, especially the King's Royal Rifle Corps or the Rifle Brigade; chiefly in plural; also occasionally attributive.
2Golf (with lower-case initials) a green sports coat awarded to the winner of the U.S. Masters Tournament.