A bomb shelter is any kind of a civil defense

Civil defense

Civil defense, civil defence or civil protection is an effort to protect the citizens of a state from military attack. It uses the principles of emergency operations: prevention, mitigation, preparation, response, or emergency evacuation, and recovery...

 structure designed to provide protection against the effects of a bomb

Bomb

A bomb is any of a range of explosive weapons that only rely on the exothermic reaction of an explosive material to provide an extremely sudden and violent release of energy...

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Types of shelter

Different kinds of bomb shelters are configured to protect against different kinds of attack and strengths of hostile explosives. For example, an Air-raid shelter

Air-raid shelter

Air-raid shelters, also known as bomb shelters, are structures for the protection of the civil population as well as military personnel against enemy attacks from the air...

 is a structure built to protect against bomber planes dropping bombs over a large area. These were commonly seen during World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

. A fallout shelter

Fallout shelter

A fallout shelter is an enclosed space specially designed to protect occupants from radioactive debris or fallout resulting from a nuclear explosion. Many such shelters were constructed as civil defense measures during the Cold War....

 is a shelter designed specifically for a nuclear war, with thick walls made from materials intended to block the radiation from fallout

Nuclear fallout

Fallout is the residual radioactive material propelled into the upper atmosphere following a nuclear blast, so called because it "falls out" of the sky after the explosion and shock wave have passed. It commonly refers to the radioactive dust and ash created when a nuclear weapon explodes...

 resulting from a nuclear explosion

Nuclear explosion

A nuclear explosion occurs as a result of the rapid release of energy from an intentionally high-speed nuclear reaction. The driving reaction may be nuclear fission, nuclear fusion or a multistage cascading combination of the two, though to date all fusion based weapons have used a fission device...

. Many such shelters were constructed as civil defense measures during the Cold War

Cold War

The Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...

. A blast shelter

Blast shelter

A blast shelter is a place where people can go to protect themselves from bomb blasts. It differs from a fallout shelter, in that its main purpose is to protect from shock waves and overpressure, instead of from radioactive precipitation, as a fallout shelter does...

 protects against more conventional bomb blasts. Its main purpose is to protect from shock wave

Shock wave

A shock wave is a type of propagating disturbance. Like an ordinary wave, it carries energy and can propagate through a medium or in some cases in the absence of a material medium, through a field such as the electromagnetic field...

s and overpressure

Overpressure

The term Overpressure is applied to a pressure difference, relative to a "normal" or "ambient" pressure, in various circumstances:* In engineering: the pressure difference over the wall thickness of a pressure vessel...

. While these forms of bomb shelters are equally amenable to civilian and military use, a bunker

Bunker

A military bunker is a hardened shelter, often buried partly or fully underground, designed to protect the inhabitants from falling bombs or other attacks...

 is more commonly associated with military use. A bunker may be hastily assembled as part of an ongoing military advance, or to hold a line. It was used during World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

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History

While military units have long built defensive structures to protect against various kinds of hostile bombardment, the use of the phrase "bomb shelter" can be traced at least as far back as 1833. A dictionary from that year defines a "casement" as "a bomb-proof shelter for soldiers in garrison". In 1881, the United States War Department issued a report in which it indicated that the defenses of Charleston, South Carolina

Charleston, South Carolina

Charleston is the second largest city in the U.S. state of South Carolina. It was made the county seat of Charleston County in 1901 when Charleston County was founded. The city's original name was Charles Towne in 1670, and it moved to its present location from a location on the west bank of the...

 included construction at Fort Moultrie of:
The shortening of this phrase to the conventional "bomb shelter" appears in print at least as early as 1895.