A militia is generally an army or some other fighting organization of non-professional and/or part-time soldiers; citizens of a country, or subjects of a state, who may perform military service during times of need. The term "militia" can apply to forces engaged in a defense activity or service, to protect a community, its territory, property, and laws. The entire able-bodied population of a community, town, county, or state available to be called to arms can also be considered a militia. The classes of the militia in the United States are the organized militia, which consists of the National Guard and the Naval Militia, and the unorganized militia, which consists of the members of the militia who are not members of the National Guard or the Naval Militia.

The term "militia" has taken on new meaning as makeshift vigilante groups have popped up with increasing frequency in the months leading up to a contentious election. Once limited to the far-right fringe, the term “militia” now encompasses a far wider spectrum, representing everything from armed-to-the-teeth neighborhood watch organizations to an all-Black paramilitary group that marches to protest police violence. The rising visibility of such groups has put a spotlight on the word “militia” itself, with many critics demanding it be replaced.