text: whats the difference between the...? marines and navy? the marines -   a marine corps (from french "corps de marine") is a branch of a nation's armed forces incorporating marines, intended to be capable of mounting amphibious assaults using infantry, armour, aircraft, and watercraft. the role of a marine corps can differ between nations. many countries, including spain, germany, france and russia describe these combatant groups as "naval infantry."  in modern warfare, marines are usually elite, highly mobile troops, and are used in situations that do not always involve naval elements. for example, the united states marine corps, the largest in the world, is often used as a spearhead for major military offensives or as a stopgap when an emergency military situation breaks out, performing critical military operations until more permanent forces arrive. historically, marines were part of the navy and served onboard warships. they assisted the crew in battles, boarded enemy ships, conducted small coastal raids, and protected the officers from mutiny by the crew. eventually they have become the primary landing force.  the navy on the other hand -   a navy is the branch of a country's military forces principally designated for naval warfare and amphibious warfare (marines) namely lake or ocean borne combat operations and related functions. it includes operations conducted by surface ships, amphibious ships, submarines, and seaborne aviation, as well as ancillary support, communications, training, and other fields; recent developments have included space related operations. the strategic offensive role of a navy is projection of force into areas beyond a country's shores (for example, to protect sea-lanes, ferry troops, or attack other navies, ports, or shore installations). the strategic defensive purpose of a navy is to frustrate sea-borne projection-of-force by enemies. the strategic task of the navy also may incorporate nuclear deterrence by use of nuclear missiles.  i.e. navy fight at sea, marines a branch of the navy that fight on land.