Navy in the context of Military branch

A military, also known collectively as armed forces, is a heavily armed, highly organized force primarily intended for warfare. Militaries are typically authorized and maintained by a sovereign state, with their members identifiable by a distinct military uniform. They may consist of one or more military branches such as an army, navy, air force, space force, marines, or coast guard. The main task of a military is usually defined as defence of their state and its interests against external armed threats.

In broad usage, the terms "armed forces" and "military" are often synonymous, although in technical usage a distinction is sometimes made in which a country's armed forces may include other paramilitary forces such as armed police.

Command of the sea (also called control of the sea or sea control) is a naval military concept regarding the strength of a particular navy to a specific naval area it controls. A navy has command of the sea when it is so strong that its rivals cannot attack it directly. This dominance may apply to its surrounding waters (i.e., the littoral) or may extend far into the oceans, meaning the country has a blue-water navy. It is the naval equivalent of air supremacy.

With command of the sea, a country (or alliance) can ensure that its own military and merchant ships can move around at will, while its rivals are forced either to stay in port or to try to evade it. It also enables free use of amphibious operations that can expand ground-based strategic options. The British Royal Navy held command of the sea for most of the period between the 18th to the early 20th centuries, allowing Britain and its allies to trade and to move troops and supplies easily in wartime, while its enemies could not. In the post-World War II period, the United States Navy has had command of the sea.

The United States Navy (USN) is the maritime service branch of the United States Armed Forces and the naval warfare force of the United States. It is the world's most powerful navy with the largest displacement, at 4.5 million tons in 2021. It has the world's largest aircraft carrier fleet, with eleven in service, one undergoing trials, two new carriers under construction, and six other carriers planned as of 2024. With 336,978 personnel on active duty and 101,583 in the Ready Reserve, the U.S. Navy is the third largest of the United States military service branches in terms of personnel. It has 299 deployable combat vessels and about 4,012 operational aircraft as of 18 July 2023. The U.S. Navy is a part of the United States Department of Defense and is one of six armed forces of the United States and one of eight uniformed services of the United States.

The United States Navy traces its origins to the Continental Navy, which was established during the American Revolutionary War and was effectively disbanded as a separate entity shortly thereafter. After suffering significant loss of goods and personnel at the hands of the Barbary pirates from Algiers, the United States Congress passed the Naval Act of 1794 for the construction of six heavy frigates, the first ships of the Navy. The United States Navy played a major role in the American Civil War by blockading the Confederacy and seizing control of its rivers. It played the central role in the World War II defeat of Imperial Japan. The United States Navy emerged from World War II as the most powerful navy in the world, succeeding the British Navy. The modern United States Navy maintains a sizable global presence, deploying in strength in such areas as the Western Pacific, the Mediterranean, and the Indian Ocean. It is a blue-water navy with the ability to project force onto the littoral regions of the world, engage in forward deployments during peacetime and rapidly respond to regional crises, making it a frequent actor in American foreign and military policy.

The Bulgarian Navy (Bulgarian: Военноморски сили на Република България, romanized: Voennomorski sili na Republika Balgariya, lit. 'Naval Forces of the Republic of Bulgaria') is the navy of the Republic of Bulgaria and forms part of the Bulgarian Armed Forces.

The Principality of Bulgaria established its navy soon after its creation, in 1879, to operate on the Danube river and the Black Sea, but the young country could spend only limited resources on warships. In the conflicts of the 20th century in which Bulgaria was involved - the Balkan Wars, World War I and World War II, the navy played a limited role, mainly protecting Bulgarian harbors and shipping. The navy's greatest combat feat was a torpedo attack against an Ottoman cruiser during the First Balkan War that forced the ship to retreat.

The Ottoman Navy (Turkish: Osmanlı Donanması) or the Imperial Navy (Ottoman Turkish: Donanma-yı Humâyûn), also known as the Ottoman Fleet, was the naval warfare arm of the Ottoman Empire. It was established after the Ottomans first reached the sea in 1323 by capturing Praenetos (later called Karamürsel after the founder of the Ottoman Navy), the site of the first Ottoman naval shipyard and the nucleus of the future navy.

During its long existence, the Ottoman Navy was involved in many conflicts and signed a number of maritime treaties. It played a decisive role in the conquest of Constantinople and the subsequent expansion into the Mediterranean and Black Seas. At its height in the 16th century, the Navy extended to the Indian Ocean, sending an expedition to Indonesia in 1565, and by the early 17th century operated as far as the Atlantic. Commensurate with the decline and modernization of the empire in the late 18th century, the Ottoman Navy stagnated, albeit remaining among the largest in the world: with nearly 200 warships, including 21 battleships, it ranked third after the British and French navies in 1875.

Naval warfare is combat in and on the sea, the ocean, or any other battlespace involving a major body of water such as a large lake or wide river.

The armed forces branch designated for naval warfare is a navy. Naval operations can be broadly divided into riverine/littoral applications (brown-water navy), open-ocean applications (blue-water navy), between riverine/littoral and open-ocean applications (green-water navy), although these distinctions are more about strategic scope than tactical or operational division. The strategic offensive purpose of naval warfare is projection of force by water, and its strategic defensive purpose is to challenge the similar projection of force by enemies.

Marines (or naval infantry) are military personnel generally trained to operate on both land and sea, with a particular focus on amphibious warfare. Historically, the main tasks undertaken by marines have included raiding ashore (often in support of naval objectives) and the boarding of vessels during ship-to-ship combat or capture of prize ships. Marines also assisted in maintaining security, discipline, and order aboard ships (reflecting the historically pressed-nature of the rest of the ship's company and the risk of mutiny). While maintaining many of their historical roles, in modern times, marines also engage in duties including rapid-response operations, humanitarian aid, disaster relief, special operations roles, and counter-terrorism operations. In most nations, marines are an integral part of that state's navy, such as the United Kingdom's Royal Marines or Russia's Naval Infantry; in some countries their marine forces can instead be part of the land army, such as the French Troupes de marine, or, more uncommonly, a nation’s marine forces may be an independent military branch such as the United States Marine Corps or the Ukrainian Marine Corps.

The exact term "marine" is not found in many languages other than English. In French-speaking countries, two terms which could be translated as "marine", but do not translate exactly: troupes de marine (marine troops) and fusiliers-marins (marine riflemen) and fuzileiros navais in Portuguese (lit. 'Naval fusiliers'). The word marine means "navy" in many European languages such as Dutch, French, German, Italian and Norwegian. “Naval infantry” may also refer to sailors forming both temporary and permanent infantry units, such as the British WWI-era 63rd (Royal Naval) Division (an infantry division made-up of Royal Navy sailors and Royal Marines on a semi-permanent basis) or the Imperial Japanese Naval Landing Forces (ad-hoc formations of Imperial Japanese Navy sailors temporarily pressed into service as infantry).

A coast guard or coastguard is a maritime security organization of a particular country. The term embraces wide range of responsibilities in different countries, from being a heavily armed military force with customs and security duties to being a volunteer organization tasked with search and rescue without law enforcement authority. In most countries, a typical coast guard's functions are distinct from those of the navy (a military service) and the transit police (a law enforcement agency), while in certain countries they have similarities to both.

A sailor, seaman, mariner, or seafarer is a person who works aboard a watercraft as part of its crew, and may work in any one of a number of different fields that are related to the operation and maintenance of a ship. While the term sailor has its etymological roots from sailing, that is a time when sailing ships were the main mode of transport at sea, it now refers to the personnel of all watercraft regardless of the type of vessel, boat or ship. It encompasses people who operate ships professionally, be it for a military (navy) or civilian (merchant navy) or for sports or recreation. In a navy, there may be further distinctions: sailor may refer to any member of the navy even if they are based on land, while seaman may refer to a specific enlisted rank. Additionally, fisherman are seen as a distinct type of sailor, that is those engaged in fishing.

Sailors have existed from the earliest periods in history as people used boats for purposes such as maritime transport. Professional sailors normally undertake training or other forms of education to develop their skills. Professional sailors are also governed by regulations, including the STCW Convention.

The Austro-Hungarian Navy or Imperial and Royal War Navy (German: kaiserliche und königliche Kriegsmarine, in short k.u.k. Kriegsmarine, Hungarian: Császári és Királyi Haditengerészet) was the naval force of Austria-Hungary. Ships of the Austro-Hungarian Navy were designated SMS, for Seiner Majestät Schiff (His Majesty's Ship). The k.u.k. Kriegsmarine came into being after the formation of Austria-Hungary in 1867, and ceased to exist in 1918 upon the Empire's defeat and subsequent collapse at the end of World War I.

Before 1867, the Imperial Austrian Navy or simply the Austrian Navy, saw action in the French Revolutionary Wars, the Napoleonic Wars, the Austrian expedition against Morocco (1829), the Second Egyptian–Ottoman War, the First and Second Wars of Italian Independence, the Second Schleswig War, and the Third War of Italian Independence. Following Austria's defeat by Prussia and Italy during the Seven Weeks' War, the Austrian Empire reformed itself into the dual monarchy of Austria-Hungary, and the navy also became the Austro-Hungarian Navy. Largely neglected by the Empire in its early years, the k.u.k. Kriegsmarine expanded along with Austro-Hungarian industrialization into one of the largest navies in the Adriatic and Mediterranean Seas. By 1914, the k.u.k. Kriegsmarine had a peacetime strength of 20,000 personnel, seeing action in the Boxer Rebellion and other conflicts before World War I.

The Imperial Japanese Navy (IJN); Kyūjitai: 大日本帝國海軍 Shinjitai: 大日本帝国海軍 Dai-Nippon Teikoku Kaigun 'Navy of the Greater Japanese Empire', or 日本海軍 Nippon Kaigun, 'Japanese Navy') was the navy of the Empire of Japan from 1868 to 1945, when it was dissolved following Japan's surrender in World War II. The Japan Maritime Self-Defense Force (JMSDF) was formed between 1952 and 1954 after the dissolution of the IJN.

The IJN was the third largest navy in the world by 1920, behind the Royal Navy and the United States Navy (USN). It was supported by the Imperial Japanese Navy Air Service for reconnaissance and airstrike operations from the fleet. It was the primary opponent of the Western Allies in the Pacific War. The IJN additionally fielded limited land-based forces, including professional marines, marine paratrooper units, anti-aircraft defense units, installation and port security units, naval police units, and ad-hoc formations of sailors pressed into service as naval infantry.

Military personnel or military service members are members of the state's armed forces. Their roles, pay, and obligations differ according to their military branch (army, navy, marines, coast guard, air force, and space force), rank (officer, non-commissioned officer, or enlisted recruit), and their military task when deployed on operations and on exercise.

The Kriegsmarine (German pronunciation: [ˈkʁiːksmaˌʁiːnə], lit. 'War Navy') was the navy of Nazi Germany from 1935 to 1945. It superseded the Imperial German Navy of the German Empire (1871–1918) and the inter-war Reichsmarine (1919–1935) of the Weimar Republic. The Kriegsmarine was one of three official branches, along with the Heer and the Luftwaffe, of the Wehrmacht, the German armed forces from 1935 to 1945.

In violation of the Treaty of Versailles, the Kriegsmarine grew rapidly during the German naval rearmament in the 1930s. The 1919 treaty had limited the size of the German navy and prohibited the building of submarines.

The Royal Canadian Navy (RCN; French: Marine royale canadienne, MRC) is the naval force of Canada. The navy is one of three environmental commands within the Canadian Armed Forces. As of February 2024, the RCN operates 12 Halifax-class frigates, 4 Kingston-class coastal defence vessels, 4 Victoria-class submarines, 5 Harry DeWolf-class offshore patrol vessels, 8 Orca-class patrol vessels, and several auxiliary vessels. Officially, the RCN consisted of 8,400 Regular Force and 4,100 Primary Reserve sailors, supported by 3,800 civilians.

Founded in 1910 as the Naval Service of Canada (French: Service naval du Canada) and given royal sanction on 29 August 1911, the RCN was amalgamated with the Royal Canadian Air Force and the Canadian Army to form the unified Canadian Armed Forces in 1968, after which it was known as Maritime Command (French: Commandement maritime) until 2011.