A dictator is a ruler (e.g. absolutist or autocratic) who assumes sole and absolute power with military control but, without hereditary ascension such as 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 (see Roman dictator and justitium).

Like the term tyrant, originally a respectable Ancient Greek title, and to a lesser degree autocrat, it came to be used almost exclusively as a non-titular term for oppressive, even abusive rule, yet had rare modern titular uses.Fact: date=August 2008

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 characterized 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.Fact: date=August 2008

The term "dictator" is comparable to (but not synonymous with) the ancient concept of a tyrant, although 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.

Roman Origin

main: Roman Dictator

In the Roman Republic the term "Dictator" did not have the negative meaning it has later assumed. Rather, a Dictator was a person given sole power (unlike the normal Roman republican practice, where rule was divided between two equal Consuls) for a specific limited period, in order to deal with an emergency. At the end of his term, the Dictator was supposed to hand over back to the normal Consular rule and give account of his actions - and Roman Dictators usually did. Citation: http://www.reference.com/browse/dictators

The term started to get its modern negative meaning with Julius Caesar making himself a Dictator without a set limit to his term, and keeping the title until his assassination (which was itself largely due to republican diehards resenting his keeping indefinite dictatorial powers).

Garibaldi as a positive dictator

Still, even in the 19th Century, the term "Dictator" did not always have negative connotations. For example, the Italian revolutionary Garibaldi, during his famous Expedition of the Thousand in 1860, proclaimed himself "Dictator of Sicily", which did not prevent him from being extremely popular in Italian and international public opinion. His usage of the term was clearly derived from the original Roman sense - i.e., a person taking power for a limited time in order to deal with an emergency (in this case, the need to unite Italy) and with the task done Garibaldi handed over power to the government of Victor Emmanuel II of Italy.