A dictator is a ruler (e.g. absolutist or autocratic) who assumes sole and absolute power (sometimes, but not always, with military control or bribes) but not officially sanctioned by heritage, as is an absolute monarch. When other states call the head of state of a particular state a dictator, that state is called a dictatorship. The word originated as the title of a magistrate in ancient Rome appointed by the Senate to rule the republic in times of emergency.
Like the term "tyrant" (which was originally a respectable Ancient Greek title), and to a lesser degree "autocrat", "dictator" came to be used almost exclusively as a non-titular term for oppressive, even abusive rule, yet had rare modern titular use.
In modern usage, the term "dictator" is generally used to describe a leader who holds and/or abuses an extraordinary amount of personal power, especially the power to make laws without effective restraint by a legislative assembly. Dictatorships are often characterised by some of the following traits: suspension of elections and of civil liberties; proclamation of a state of emergency; rule by decree; repression of political opponents without abiding by rule of law procedures; these include single-party state, and cult of personality.
The term "dictator" is comparable to–but not synonymous with–the ancient concept of a tyrant; initially "tyrant", like "dictator", did not carry negative connotations. A wide variety of leaders coming to power in a number of different kinds of regimes, such as military juntas, single-party states and civilian governments under personal rule, have been described as dictators. They may hold left or right-wing views, or can even be apolitical.