Who gave Plato's Republic its name?

Anybody know? What is the history of the name of that dialogue? Why do we call it what we do?

Thanks in advance.

You mean the English title?

This is what Wikipedia says about it:

The English translation of the title of Plato’s dialogue is derived from Cicero’s De re publica, a dialogue written some three centuries later. Cicero’s dialogue imitates the style of the Platonic dialogues, and treats many of the topics touched upon in Plato’s Republic. Scipio Africanus, the main character of Cicero’s dialogue expresses his esteem for Plato and Socrates when they are talking about the “Res publica”. “Res publica” is not an exact translation of the Greek word “politeia” that Plato used in the title of his dialogue: “politeia” is a general term indicating the various forms of government that could be used and were used in a Polis or city-state.

Robin Waterfield, in the introduction to his edition of Republic (published under the Oxford World’s Classics series, if you’re looking for it), writes:

The title > Republic > is a bad translation of the Greek > politeia> . The Greek word does occur a number of times in the book, as well as forming the title […]. > Politeia > is the public and political life of a community; in Latin this is > res publica> , ‘public business’; Greek works used to be referred to by their Latin or Latinized titles: hence > Republic> . (pp. xi-xii)

If I’m reading the academic material correctly, the name ΠΟΛΙΤΕΙΑ was given to the work by Plato himself. Since classicists are traditionally perverse enough to write their commentaries and annotations to Greek texts in Latin, the title Res Publica (which, at least by Latin standards, is a fairly sensible rendering of the Greek) gained currency, and from there became the English Republic — which, unfortunately, has gained a fair amount of meaning on its own that isn’t present in the original Latin or Greek words.