Corps (//; plural corps //; from French corps, from the Latin corpus "body") is a term used for several different kinds of organization. A military innovation by Napoleon, the formation was first named as such in 1805. The size of a corps varies greatly, but from two to five divisions and anywhere from 40,000 to 80,000 are the numbers stated by the US Department of Defense.
Within military terminology a corps may be:
- an operational formation, sometimes known as a field corps, which consists of two or more divisions, such as the Corps d'armée, later known as I Corps ("First Corps") of Napoleon's Grande Armée);
- an administrative corps (or mustering) – that is a specialized branch of a military service (such as an artillery corps, a medical corps, or a force of military police) or;
- in some cases, a distinct service within a national military (such as the United States Marine Corps).
These usages often overlap.