What is Dictator Perpetuo?

Legal Definition
Dictator perpetuo (English: "dictator in perpetuity"), also called dictator in perpetuum, was the office held by Julius Caesar from 26 January or 15 February of the year 44 BCE until his death on 15 March. By abandoning the time restrictions usually applied in the case of the Roman dictatura, it elevated Caesar's dictatorship into the monarchical sphere.

Julius Caesar held the dictator position for only eleven days in 49 BCE (holding elections either as dictator Comit. habend. or as dictator rei gerundae causa) and again for the year 48/47 BCE. In 46 BCE, he was elected dictator for the next ten years. At some point between January and February 44 BCE he was appointed dictator perpetuo, but was assassinated less than two months later (on the Ides of March).

Dictator perpetuo is often mistranslated as "dictator for life", but the title did not imply that Caesar would never resign it. Weinstock has argued that the perpetual dictatorship was part of the senatorial decrees regarding Caesar's divine honors, as well as his planned apotheosis as Divus Iulius, a complex of honors aimed at eternity and divinity.
-- Wikipedia