What is rhetoric?

https://rhetoric.sdsu.edu/resources/what_is_rhetoric.htm

Extract:

Cicero (ca. 90 BCE):

There is a scientific system of politics which includes many important departments. One of these departments—a large and important one—is eloquence based on the rules of art, which they call rhetoric. For I do not agree with those who think that political science has no need for eloquence, and I violently disagree with those who think that it is wholly comprehended in the power and skill of the rhetorician. Therefore we will classify oratorical ability as a part of political science. The function of eloquence seems to be to speak in a manner suited to persuade an audience, the end is to persuade by speech.

Friedrich Nietzsche (1872-73):

What is called “rhetorical,” as a means of conscious art, had been active as a means of unconscious art in language and its development, indeed, that the rhetorical is a further development, guided by the clear light of the understanding, of the artistic means which are already found in language. There is obviously no unrhetorical “naturalness” of language to which one could appeal; language itself is the result of purely rhetorical arts. The power to discover and to make operative that which works and impresses, with respect to each thing, a power which Aristotle calls rhetoric, is, at the same time, the essence of language; the latter is based just as little as rhetoric is upon that which is true, upon the essence of things. Friedrich Nietzsche on Rhetoric and Language, p 21.

Steven Mailloux (1989):

[Rhetoric is] the political effectivity of trope and argument in culture. Such a working definition includes the two traditional meanings of rhetoric—figurative language and persuasive action—and permits me to emphasize either or both senses, differently in different discourse at different historical moments, in order to specify more exact