Military personnel is a blanket term used to refer to members of any armed force. Usually, military personnel are divided into branches of service roughly defined by certain circumstances of the deployment of the personnel. Those who serve in a typical large land force are soldier

Soldier

A soldier is a member of the land component of national armed forces; whereas a soldier hired for service in a foreign army would be termed a mercenary...

s, making up an army

Army

An army An army An army (from Latin arma "arms, weapons" via Old French armée, "armed" (feminine), in the broadest sense, is the land-based military of a nation or state. It may also include other branches of the military such as the air force via means of aviation corps...

. Those who serve in seagoing forces are seamen

Seaman

Seaman is one of the lowest ranks in a Navy. In the Commonwealth it is the lowest rank in the Navy, followed by Able Seaman and Leading Seaman, and followed by the Petty Officer ranks....

, and their branch is a navy

Navy

A navy is the branch of a nation's armed forces principally designated for naval and amphibious warfare; namely, lake- or ocean-borne combat operations and related functions...

. Marines serve in a marine corps

Marine corps

A marine is a member of a force that specializes in expeditionary operations such as amphibious assault and occupation. The marines traditionally have strong links with the country's navy...

. In the twentieth century, the development of powered flight prompted the development of air force

Air force

An air force, also known in some countries as an air army, is in the broadest sense, the national military organization that primarily conducts aerial warfare. More specifically, it is the branch of a nation's armed services that is responsible for aerial warfare as distinct from an army, navy or...

s, serviced by airmen

Airman

An airman is a member of the air component of a nation's armed service. In the United States Air Force and the Royal Air Force , it can also refer to a specific enlisted rank...

.