Anarchy, the meaning of it comes from the ancient Greek ἀναρχία, anarchic, from ἀν an, "not" + ἀρχός ark-hos, "ruler", meaning "absence of a leader", "without rulers", has more than one definition. In the United States, the term "anarchy" typically is used to refer to a society without a publicly enforced government or violently enforced political authority. When used in this sense, anarchy may or may not be intended to imply political disorder or lawlessness within a society. However, this usage is not the traditional sense of the word.
Outside of the US, and by most individuals that self-identify as anarchists, it implies a system of governance, mostly theoretical at a nation state level although there are a few successful historical examples, that goes to lengths to avoid the use of coercion, violence, force and authority, while still producing a productive and desirable society.
Anarchism is generally defined as the political philosophy which holds the state to be immoral, or alternatively as opposing authority in the conduct of human relations. Proponents of anarchism (known as "anarchists") advocate stateless societies based on non-hierarchical voluntary associations.
There are many types and traditions of anarchism, not all of which are mutually exclusive. Anarchist schools of thought can differ fundamentally, supporting anything from extreme individualism to complete collectivism. Strains of anarchism have been divided into the categories of social and individualist anarchism or similar dual classifications. Anarchism is often considered to be a radical left-wing ideology, and much of anarchist economics and anarchist legal philosophy reflect anti-statist interpretations of communism, collectivism, syndicalism or participatory economics. However, anarchism has always included an individual strain supporting a market economy and private property, or morally unrestrained egoism. Some individualist anarchists are also socialists or communists while some anarcho-communists are also individualists or egoists.
Anarchism as a social movement has regularly endured fluctuations in popularity. The central tendency of anarchism as a mass social movement has been represented by anarcho-communism and anarcho-syndicalism, with individualist being primarily a literary phenomenon which nevertheless did have an impact on the bigger currents and individualists also participated in large anarchist organizations. Most anarchists oppose all forms of aggression, supporting self-defense or non-violence (anacho-pacifism), while others have supported the use of some coercive measures, including violent revolution and propaganda of the deed, on the path to an anarchist society.
The term anarchism derives from the Greek ἄναρχος, anarchos, meaning "without rulers", from the prefix ἀν- (an-, "without") + ἀρχή (archê, "sovereignty, realm, magistracy") + -ισμός (-ismos, from the suffix -ιζειν, -izein "-izing"). There is some ambiguity with the use of the terms "libertarianism" and "libertarian" in writings about anarchism. Since the 1890s from France, the term "libertarianism" has often been used as a synonym for anarchism and was used almost exclusively in this sense until the 1950s in the United States; its use as a synonym is still common outside the United States. Accordingly, "libertarian socialism" is sometimes used as a synonym for socialist anarchism, to distinguish it from "individualist libertarianism" (individualist anarchism). On the other hand, some use "libertarianism" to refer to individualistic free-market philosophy only, referring to free-market anarchism as "libertarian anarchism".