Military base
Jurisdictional definition: Military bases within the United States are considered federal property and are subject to federal law. Civilians (such as family members of military officers) living on military bases are generally subject to the civil and criminal laws of the states where the bases are located. Military bases can range from small outposts to military cities containing up to 100,000 people. A military base may belong to a different nation or state than the territory surrounding it.

Naming: The name used generally refers to the type of military activity that takes place at the base, as well as the traditional nomenclature used by a branch of service.
A military base may go by any of a number of names, such as the following:

Types of establishment: Depending on the context, the term "military base" may refer to any establishment (usually permanent) that houses a nation's armed forces, or even organized paramilitary forces such as the police, constabulary, militia, or national guards. Alternatively, the term may refer solely to an establishment which is used only by an army (or possibly other land fighting related forces, such as marines) to the exclusion of a base used by either an air force or a navy. This is consistent with the different meanings of the word 'military'.
Some examples of permanent military bases used by the navies and air forces of the world are the HMNB Portsmouth in Portsmouth, UK, the Naval Air Station Whidbey Island, Washington State, US, or Ramstein Air Base, Germany (the last two are each designated as a Main Operating Base). Other examples of non- or semi-permanent military bases include a Forward Operating Base (FOB), a Logistics Base (Log base) and a Fire Base (FB).
A military base may also contain large concentrations of military supplies in order to support military logistics. Most military bases are restricted to the public and usually only authorized personnel may enter them (be it military personnel or their relatives and authorized civilian personnel).
In addition to the main military facilities on a certain installation, military bases usually (but not always) have various different facilities for military personnel. These facilities vary from country to country. Military bases can provide housing for military personnel, a post office and dining facilities (restaurants).  They may also provide support facilities such as fast food restaurants, gas stations, chapels, schools, banks, thrift stores, a hospital or clinic (dental or health clinics, as well as veterinarian clinics), lodging, movie theaters, and, in some countries, retail stores (usually a supermarket such as Commissary and a Department Store, such as AAFES). On American military installations, Family, Morale, Welfare and Recreation (FMWR)  provides facilities such as fitness centers, libraries, golf courses, travel centers, community service centers, campgrounds, child development centers, youth centers, automotive workshops, hobby/arts and crafts centers, bowling centers, and community centers.

Bases used by the United States Air Force Reserve tend to be active USAF bases. However, there are a few Air Reserve Bases, such as Dobbins ARB, Georgia, and Grissom ARB, Indiana, both of which are former active-duty USAF bases. Facilities of the Air National Guard are often located on civil airports in a secure cantonment area not accessible to the general public, though some units are based on USAF bases, and a few ANG-operated bases, such as Selfridge ANGB, Michigan. Support facilities on Air National Guard and Air Force Reserve installations tend to not be as extensive as active bases (i.e., they usually do not have on-base lodging (though Kingsley Field ANGB, Oregon, is an exception), clinics (except for drill days), or retail stores (although some have small convenience stores)).
In Russian usage "military base" or "naval base" is not limited to denoting a specific fence described facility and usually encompasses a broad territory within which a number of discrete facilities may be located. As examples, 1) the Russian Sevastopol Naval Base comprises individual facilities located within the city of Sevastopol proper (waterfront moorings, weapons stores, a headquarters compound, and a naval infantry base) as well as an airfield at Kacha north of the city; 2) the Leningrad Naval Base comprises all naval facilities in the greater St. Petersburg area including training schools, commissioning institutes, the naval academy, and the Kronshtadt base on Kotlin island.

Overseas military base: An overseas military base is a military base that is geographically located outside of the territory of the country whose armed forces are the principal occupants of the base.
Such bases may be established by treaties between the governing power in the host country and another country which needs to establish the military base in the host country for various reasons, usually strategic and logistic.
Furthermore, overseas military bases often serve as the source of the military brat subculture due to the children of the bases' occupant military being born or raised in the host country but raised with a remote parental knowledge of the occupant military's home country.

British military bases: In the 18th and 19th centuries the Royal Engineers were largely responsible for erecting military bases in the British Isles and the British Empire. In 1792 the Chief Engineer was instructed to prepare the Barrack Construction estimates for Parliament and at the same time the Department of the Barrackmaster-General was established.
During the period from the 1840s through the 1860s barracks were constructed under supervision of the Royal Engineers in:

Bristol (1847)
Preston (1848)
Tower of London (1851)
Sheerness (1854)
Sheffield (1854)
Curragh Camp (1855)
Devonport (1856)
Chelsea (1861)
The Cardwell Reforms (1872) ushered in another period of intensive Barrack building at Aldershot, Portsmouth, Plymouth, London, Woking, Woolwich, Dublin, Belfast, Malta, Gibraltar and the Cape of Good Hope.
In 1959 the Corps' Work Services was transferred to the civilian War Department Works Organization (later renamed Property Services Agency (PSA)) and by 1965 the (Specialist Teams Royal Engineers (STRE)) were formed to plan and execute Works projects worldwide.
Some British and Commonwealth naval bases are traditionally named, commissioned, and administered as though they were naval ships. For this reason they are sometimes called stone frigates.

Related term: Billet
Kaserne

See also: List of United States military bases
List of military bases

References: 

External links: 
Official Directory of US Military bases.
Royal Engineers Museum Military Works (construction)
New US Military Bases: Side Effects Or Causes Of War? by Zoltan Grossman
US Office of the Deputy Under Secretary of Defense (Installations and Environment)
Outposts of Empire – Booklet and map of the American military bases in the world. Transnational Institute, March 2007