(US, military) Ellipsis of American Legion.

(military, Ancient Rome) The major unit or division of the Roman army, usually comprising 3000 to 6000 infantry soldiers and 100 to 200 cavalry troops.

(military) A combined arms major military unit featuring cavalry, infantry, and artillery, including historical units such as the British Legion, and present-day units such as the Spanish Legion and the French Foreign Legion.

(military) A large military or semi-military unit trained for combat; any military force; an army, regiment; an armed, organized and assembled militia.

(often Legion or the Legion) A national organization or association of former servicemen, such as the American Legion.

A large number of people; a multitude.

(often plural) A great number.

(transitive) To form into legions.

Numerous; vast; very great in number