Militia
Etymology: Militia derives from Latin roots:

miles /miːles/ : soldier
-itia /iːtia/ : a state, activity, quality or condition of being
militia /mil:iːtia/: Military service
The word militia dates back to ancient Rome, and more recently to at least 1590 when it was recorded in a book by Sir John Smythe, Certain Discourses Military with the meanings: a military force; a body of soldiers and military affairs; a body of military discipline
The word Militia comes from ancient Latin, in which it meant defense service, as distinguished from a body of (armed) defenders which would be volgus militum. The term is used by several countries with the meaning of "defense activity" indicating it is taken directly from Latin.

Afghanistan: Militias have been used throughout the history of Afghanistan. Afghan Militias and irregular forces have contributed significantly to the military history of the country and affected the process of state formation.

Andorra: Andorra has a small army, which has historically been raised or reconstituted at various dates, but has never in modern times amounted to a standing army. The basic principle of Andorran defence is that all able-bodied men are available to fight if called upon by the sounding of the Sometent. Being a landlocked country, Andorra has no navy.
Before World War I, Andorra maintained an armed militia force of about 600 part-time militiamen under the supervision of a Captain (Capità or Cap de Sometent) and a Lieutenant (Desener or Lloctinent del Capità). This body was not liable for service outside the principality and was commanded by two officials (veguers) appointed by France and the Bishop of Urgell.
In the modern era, the army has consisted of a very small body of volunteers willing to undertake ceremonial duties. Uniforms and weaponry were handed down from generation to generation within families and communities.
The army's role in internal security was largely taken over by the formation of the Police Corps of Andorra in 1931. Brief civil disorder associated with the elections of 1933 led to assistance being sought from the French National Gendarmerie, with a detachment resident in Andorra for two months under the command of René-Jules Baulard. The Andorran Police was reformed in the following year, with eleven soldiers appointed to supervisory roles. The force consisted of six Corporals, one for each parish (although there are currently seven parishes, there were only six until 1978), plus four junior staff officers to co-ordinate action, and a commander with the rank of major. It was the responsibility of the six corporals, each in his own parish, to be able to raise a fighting force from among the able-bodied men of the parish.
Today a small, twelve-man ceremonial unit remains the only permanent section of the Sometent, but all able-bodied men remain technically available for military service, with a requirement for each family to have access to a firearm. An area weapon such as a Shotgun per household is unregulated, however ranged weapons such as Pistols and Rifles require a license. The army has not fought for more than 700 years, and its main responsibility is to present the flag of Andorra at official ceremonial functions. According to Marc Forné Molné, Andorra's military budget is strictly from voluntary donations, and the availability of full-time volunteers.
In more recent times there has only been a general emergency call to the popular army of Sometent during the floods of 1982 in the Catalan Pyrenees, where 12 citizens perished in Andorra, to help the population and establish a public order along with the Local Police units.

Argentina: In the early 1800s Buenos Aires, which was by then the capital of the Viceroyalty of the Río de la Plata, was attacked during the British invasions of the Río de la Plata. As regular military forces were insufficient to counter the British attackers, Santiago de Liniers drafted all males in the city capable of bearing arms into the military. These recruits included the criollo peoples, who ranked low down in the social hierarchy, as well as some slaves. With these reinforcements, the British armies were twice defeated. The militias became a strong factor in the politics of the city afterwards, as a springboard from which the criollos could manifest their political ambitions. They were a key element in the success of the May Revolution, which deposed the Spanish viceroy and began the Argentine War of Independence. A decree by Mariano Moreno derogated the system of promotions involving criollos, allowing instead their promotion on military merit.
The Argentine Civil War was waged by militias again, as both federalists and unitarians drafted common people into their ranks as part of ongoing conflicts. These irregular armies were organized at a provincial level, and assembled as leagues depending on political pacts. This system had declined by the 1870s, mainly due to the establishment of the modern Argentine Army, drafted for the Paraguayan War by President Bartolomé Mitre. Provincial militias were outlawed and decimated by the new army throughout the presidential terms of Mitre, Sarmiento, Avellaneda and Roca.

Armenia: Armenian militia, or fedayi played a major role in the independence of various Armenian states, including Western Armenia, the First Republic of Armenia, and the Republic of Artsakh. Armenian militia also played a role in the Georgia-Abkhazia War of 1992–1993.

Australia: In the Colony of New South Wales, Governor Lachlan Macquarie proposed a colonial militia but the idea was rejected. Governor Ralph Darling felt a mounted police force was more efficient than a militia. A military volunteer movement attracted wide interest during the Crimean War. Following Federation, the various military reserve forces of the Commonwealth of Australia became the Citizen Military Force (CMF).
A citizens' militia modeled on the British Home Guard called the Volunteer Defence Corps (VDC) was founded by the Returned and Services League of Australia (RSL) in 1940 in response to the possibility of a Japanese invasion of Australia. In the beginning, members didn't have uniforms and often paraded in business attire. They were given instruction on guerrilla warfare, and later the private organization was taken over by the Australian Government and became part of the Australian Military Forces (AMF). The government supported the organization and equipped them with anti-aircraft artillery; however, they were disbanded by the end of World War II due to the fact that there was no longer a significant threat to national security.

Austria: During the Revolutions of 1848 in the Austrian Empire, a National Guard was established in Vienna. A separate but related Academic Legion was composed mainly of students in the capital city.
After World War I, multiple militias formed as soldiers returned home to their villages, only to find many of them occupied by Slovene and Yugoslav forces. Especially in the southern province of Carinthia the Volkswehr (Peoples Defense Force) was formed, to fight the occupant forces.
During the First Republic, similar to the development in Germany, increasing radicalization of politics led to certain paramilitary militias associating with certain political parties. The Heimwehr (German: Home Defense) became affiliated with the Christian Social Party and the Republikanischer Schutzbund (German: Republican Defense League) became affiliated with the Social Democratic Workers' Party of Austria. Violence increasingly escalated, breaking out during the July Revolt of 1927 and finally the Austrian Civil War, when the Schutzbund was defeated by the Heimwehr, police, Gendarmerie and Austrian Armed Forces.
After World War II the Austrian Armed Forces (Bundesheer) were reestablished as a conscript military force. A basic part of it is the militia, which is a regular reservists force of the Bundesheer, comparable to the national guard units of the United States. The conscript soldiers of the militia have to store their military equipment at home, to be mobilized quite fast within a few days in case of emergency. The system was established during the Cold War and still exists, but the members of the militia now are volunteers only.

Bahrain: In Bahrain, emergence of a small militia group Katibat al Haydariyah was first seen in 2015. During the year, total four attacks were claimed by the group, including on August 22 and 24, 2015, in Muharraq, on September 10, 2015, in Al Khamis, and on October 9, 2015, on Bahraini forces in the Al Juffair region. Katibat al Haydariyah is its own distinct organization that decries the Bahraini government, but Canada and the United Kingdom listed it as an alias for the larger Al-Ashtar Brigades (or the Saraya al Ashtar). After four years, the militia group reemerged on social media in October 2019, to threaten new attacks on the island. It stated that they “will not retreat from our goals of the downfall of the Al Khalifa entity,” and that “soon, guns will open their mouths and they will hear the whiz of bullets”.

Belgium: The Garde Civique or Burgerwacht (French and Dutch; "Civic Guard") was a Belgian paramilitary militia which existed between 1830 and 1920.