Seaman is one of the lowest ranks in 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...

. In the Commonwealth

Commonwealth of Nations

The Commonwealth of Nations, normally referred to as the Commonwealth and formerly known as the British Commonwealth, is an intergovernmental organisation of fifty-four independent member states...

 it is the lowest rank in the Navy, followed by Able Seaman

Able Seaman (rank)

In the British Royal Navy in the middle of the 18th century, the term able seaman referred to a seaman with at least two years' experience at sea...

 and Leading Seaman

Leading Seaman

Leading seaman is a junior non-commissioned rank or rate in navies, particularly those of the Commonwealth. When it is used by NATO nations, leading seaman has the rank code of OR-4. It is often equivalent to the army and air force rank of corporal and some navies use corporal rather than...

, and followed by the Petty Officer

Petty Officer

A petty officer is a non-commissioned officer in many navies and is given the NATO rank denotion OR-6. They are equal in rank to sergeant, British Army and Royal Air Force. A Petty Officer is superior in rank to Leading Rate and subordinate to Chief Petty Officer, in the case of the British Armed...

 ranks.

In the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, it means the lowest three enlisted rates of the U.S. Navy

United States Navy

The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...

, followed by the higher Petty Officer

Petty Officer

A petty officer is a non-commissioned officer in many navies and is given the NATO rank denotion OR-6. They are equal in rank to sergeant, British Army and Royal Air Force. A Petty Officer is superior in rank to Leading Rate and subordinate to Chief Petty Officer, in the case of the British Armed...

 ranks. The equivalent of the seaman, in French-speaking countries, is the Matelot.

The term "seaman" is also a general-purpose for a man or a woman who works anywhere on board a modern ship, including in the engine spaces, which is the very opposite of sailing.