Legion

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

A combined arms major military unit featuring cavalry, infantry, and artillery

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.

To form into legions.

Numerous; vast; very great in number

"Russia’s labor and capital resources are woefully inadequate to overcome the state’s needs and vulnerabilities, which are legion."