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A rearguard or rear security is a part of a
military
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 d ...
force that protects it from attack from the rear, either during an advance or
withdrawal. The term can also be used to describe forces protecting lines, such as
communication lines, behind an army. Even more generally, a rearguard action may refer
idiom
An idiom is a phrase or expression that largely or exclusively carries a Literal and figurative language, figurative or non-literal meaning (linguistic), meaning, rather than making any literal sense. Categorized as formulaic speech, formulaic ...
atically to an attempt at preventing something though it is likely too late to be prevented; this idiomatic meaning may apply in either a military or non-military context.
Origins
The term rearguard (also ''rereward'', ''rearward'') comes from the
Old French
Old French (, , ; ) was the language spoken in most of the northern half of France approximately between the late 8th ''reregarde'', i.e. "the guard which is behind", originating with the medieval custom of dividing an army into three ''
battles'' or ''wards''; Vanguard">Van, Main (or Middle) and Rear. The Rear Ward usually followed the other wards on the march and during a battle usually formed the rearmost of the three if deployed in
column
A column or pillar in architecture and structural engineering is a structural element that transmits, through compression, the weight of the structure above to other structural elements below. In other words, a column is a compression member ...
or the left-hand ward if deployed in Line (formation)">line.
Original usage

The commonly accepted definition of a rearguard in military tactics was largely established in the battles of the late 19th century. Before the mechanization of troop formations, most rearguard tactics originally contemplated the use of cavalry forces. This definition was later extended to highly mobile infantry as well as mechanized or armored forces.
Narrowly defined, a rearguard is a covering detachment that protects the retreating main ground force element (main body), or column, and is charged with executing defensive or retrograde movements between the main body and the enemy to prevent the latter from attacking or interfering with the movement of the main body.
Contemporary usage

A more expansive definition of the rearguard arose during the large-scale struggles between nation-states during
World War I
World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...
and
World War II
World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...
. In this context, a rearguard can be a minor unit of regular or irregular troops that protect the withdrawal of larger numbers of personnel (military or civilian) during a retreat, by blocking, defending, delaying, or otherwise interfering with enemy forces in order to gain time for the remainder to regroup or reorganize. Rearguard actions may be undertaken in a number of ways: defensively, such as by defending strongpoints or tactically important terrain; or offensively, by pre-emptively assaulting with a ''spoiling attack'' an enemy that is preparing offensive operations.
Three examples of rearguard actions are:
*
Rorke's Drift during the
Zulu War (1879)
[Crowley, Liz and Hand, David. ]
Football, Europe and the Press
', p. 31 (Routledge 2013).
*
Battle of Tirad Pass (1899)
*
Battle of Dunkirk
The Battle of Dunkirk () was fought around the French Third Republic, French port of Dunkirk, Dunkirk (Dunkerque) during the Second World War, between the Allies of World War II, Allies and Nazi Germany. As the Allies were losing the Battle ...
(1940)
A
World War I
World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...
-era example is the rearguard action fought by small units of the
Serbian Army to protect retreating Serbian troops, the
royal family
A royal family is the immediate family of monarchs and sometimes their extended family.
The term imperial family appropriately describes the family of an emperor or empress, and the term papal family describes the family of a pope, while th ...
, and Serbian refugees from advancing forces of the
Central Powers
The Central Powers, also known as the Central Empires,; ; , ; were one of the two main coalitions that fought in World War I (1914–1918). It consisted of the German Empire, Austria-Hungary, the Ottoman Empire, and the Kingdom of Bulga ...
during their
retreat through Albania and Montenegro in 1915–1916. The nature of combat in rearguard actions involving combat between armies of nation-states is typically desperate and vicious, and rearguard troops may be called upon to incur heavy casualties or even to sacrifice all of their combat strength and personnel for the benefit of the withdrawing forces.
Idiomatic expression
Fighting or mounting a rearguard action is also sometimes an
idiom
An idiom is a phrase or expression that largely or exclusively carries a Literal and figurative language, figurative or non-literal meaning (linguistic), meaning, rather than making any literal sense. Categorized as formulaic speech, formulaic ...
atic expression, outside any military context. That idiom refers to trying very hard to prevent a thing from happening even though it is probably too late.
Cambridge Idioms Dictionary
' (2nd ed., Cambridge University Press, 2006) via ''The Free Dictionary
''The Free Dictionary'' is an American online dictionary and encyclopedia that aggregates information from various sources. It is accessible in fourteen languages.
History
The Free Dictionary was launched in 2005 by Farlex. In the same year, ...
''. An example of a famous rearguard action outside the military context is the effort by Roman emperor
Julian around 362 A.D. to restore
Paganism
Paganism (, later 'civilian') is a term first used in the fourth century by early Christians for people in the Roman Empire who practiced polytheism, or ethnic religions other than Christianity, Judaism, and Samaritanism. In the time of the ...
as the state religion instead of Christianity. Sportswriters employ the idiom as well.
[Reavis, Tracey. ]
The Life and Career of David Beckham: Football Legend, Cultural Icon
', p. 70 (Rowman & Littlefield, 2014).
See also
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Quick reaction force
A rapid reaction force / rapid response force (RRF), quick reaction force / quick response force (QRF), immediate reaction force (IRF), rapid deployment force (RDF), or quick maneuver force (QMF) is a military or Law enforcement agency, law enf ...
*
Second line
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Vanguard
The vanguard (sometimes abbreviated to van and also called the advance guard) is the leading part of an advancing military formation. It has a number of functions, including seeking out the enemy and securing ground in advance of the main force.
...
References
{{Authority control
Military tactics