Is the United States a democracy, or a republic? (Both.) What's the difference between an autocracy and a dictatorship? (There is none.) These and other questions of usage are answered with definitions and connotations of terms referring to forms and philosophies of government listed below:
1. Anarchy: Anarchy is from the Greek word meaning "no rule" and refers to a society without government. Because this is an impractical if not impossible condition, it is generally used in a looser sense of chaos.
2. Authoritarian: Less a form of government than a description, this term connotes an oppressive form of rule in which citizens' rights are restricted, putatively for the society's security and stability. A single head of state often dominates a country with authoritarian rule, but it's likely that more than one person has significant power.
3. Autocracy: An autocracy (from the Greek words for "self" and "rule" but referring not to self-determination but to "one who rules by himself") is a government led by one person with dictatorial power.
4. Cabal: Ultimately derived from the Hebrew word adopted for the name of the mystical Kabbalah philosophy of Judaism, cabal refers not to a form of government but to the machinations of an insurrectionary group, or to the group itself. (By extension, it can refer to any group outside of the political realm.) The term, thanks to its frequent use by conspiracy theorists, has an unfortunate association with paranoid delusions about secret societies and behind-the-scenes manipulation of government affairs.
5. Dictatorship: This term, stemming from the Latin word meaning "to declare" and originally a reference to a temporary emergency government established by the Roman Senate, now refers to an autocratic rule by one or more people. The word has a negative connotation and is rarely or ever used by such a government.
6. Federation: A federation (the word is from the Latin term for "compact" or "league" and ultimately derived from the word for "trust") is a form of government in which subordinate jurisdictions such as states or provinces reserve some sovereignty and/or rights under a national government. (A related term, confederation, implies a more loosely allied group of sovereign states.)
7. Junta: This term — also spelled junto and derived from the Spanish word for "joined," refers to a postrevolutionary government and carries a sense of a tightly controlled government.
8. Democracy: In its literal sense, a democracy is, as its Greek etymology specifies, a rule of the people. In practice, however, the term is interchangeable with republic, in that it refers to a system of government in which the will of the people is carried out by elected representatives.
9. Monarchy: A monarchy (from the Greek term meaning "rule by one") is a government led by a person usually selected by hereditary succession. However, the ruler's authority may vary from nominal (a figurehead) to absolute (a despot). Most current monarchies are technically constitutional, or limited, monarchies, meaning that the ruler is subject to laws that protects citizens' rights.
10. Oligarchy: No government is literally an oligarchy (the word is from the Greek term for "rule of the few"), but that description is used often to refer to the fact that a nation's wealthiest people generally have an inordinate influence on governance because of their ties to elected officials. The implication is that a government so influenced is corrupt and predicated on the oligarchy's self-interest.
11. Regime: The Merriam-Webster's Collegiate Dictionary definition of this term — "lawful control over the affairs of a political unit" — is oddly neutral, considering that the connotation is invariably of a repressive dictatorship.
12. Republic: A republic (the word is Latin for "public thing") is a government whose authority is based on citizen voters represented by elected officials chosen in free elections, as opposed to a monarchy or a dictatorship.
13. Theocracy: A theocracy, from the Greek word meaning "rule of God," refers to a government controlled by religious authorities. The connotation is that the government is repressive and intolerant of values that conflict with the dominant theology.
14. Totalitarian: Derived from the Italian word for "totality," this word describes a dictatorial government.
15. Tyranny: Tyranny is a condition in which a nation is under the rule of a tyrant, who seized power illegally and governs with few or no checks and balances. The term was originally a neutral word meaning "monarchy," but it acquired the connotation of "despot" and is by extension often employed to an overbearing authority figure such as a parent or a boss.
Thanks to Mark Nichol / Daily Writing Tips