Marines (from the English adjective marine, meaning of the sea, from Latin language mare, meaning sea, via French adjective marin(e), of the sea) are military forces optimised for operations at sea. Historically marine forces are part of a navy, however in some countries the marine force is under independent command.

Tasks undertaken by marines have included providing security in a warship whilst at sea, reflecting the pressed nature of the ships' company and the risk of mutiny. Other tasks would include boarding of vessels during combat or capture of prize ships and providing manpower for raiding ashore in support of the naval objectives. Marine elements would also contribute to the campaign ashore, in support of the military objective.

With the industrialisation of warfare in the 20th Century the scale of landing operations increased, and brought with it an increased likelihood of opposition, and a need for co-ordination of various military elements. Marine forces evolved to specialise in the skills and capabilities required for amphibious warfare.

The exact term marine does not exist in many other languages. Typically, foreign equivalents are called naval infantry (e.g., as in Spain, Germany, and Russia). In French-speaking countries, two terms exist which could be translated as marine: troupes de marine and fusiliers-marins; similar pseudo-translations exist elsewhere, e.g., Fuzileiros Navais in Portuguese. The word marine means Navy in many European languages such as Spanish, French, German, Dutch, Swedish and Norwegian.

Roles

The principal role of marine troops is military operations in the littoral zone, operating from ships they are trained to land on and secure key points to around 50 miles inland.

Marine units primarily deploy from warships using helicopter, landing craft, hovercraft or amphibious vehicles with some force elements capable of parachute insertion.

In addition to their primary role, marine troops are also used in a variety of other naval roles such as boarding operations, ship and port security or riverine operations

Abkhazia

• The Military of Abkhazia maintains a small Naval Infantry Battalion.

Argentina

• The Naval Infantry of the Armada of the Argentine Republic (Infantería de Marina de la Armada de la República Argentina, IMARA) is a part of the Argentine Navy. Argentine Marines have the same rank insignia and titles as the rest of the Navy. It is composed of a Fleet Marine Force (one Marine Battalion, plus artillery, air defence, communications, logistics, engineer and vehicle units), a Southern Marine Force (2 Marine Battalions), a River Operations Battalion, a Special Forces Unit (the Amphibious Commandos Group) and several Security Battalions and Companies. The 5th Battalion of the Infanteria de Marina fought and lost against three British battalions in the Falklands War ( ).