[quote=Magic Magnum]
Yet you just confused me... :/
[/quote]

Corpsman (Hospital Corpsman) = U.S. Marine Corps term for an enlisted medical specialist.

Medic (Combat Medic) = U.S. Army term for military personnel who are responsible for providing first aid and frontline trauma care on the battlefield.

It's generally seen as an insult to confuse the two. Just like it is to call a Marine; Soldier or Trooper and vice versa.