In the opening, Foss gives the definition of rhetoric as "The human use of symbols to communicate". (Foss pg 1) Later on though, she says "Rhetoric often involves the deliberate and conscious choice of symbols to communicate with others". (Foss pg 3) This second definition is closer to her explanation of rhetoric. When explaining what rhetoric is, one of the most important parts is that while communication may be accidental, rhetoric is purposeful, deliberately choosing symbols that convey what you want them to. For example, using a red circle with a line slashed over it is a symbol that something is forbidden, or an arrow is a symbol meaning "go that way".
I have always seen rhetoric as not only the process of communication, but as a way of making an argument. Rhetoric is not used just to speak, but to convince others of your point. For instance, in a debate or speech, rhetoric would be used to make a convincing argument for your side. Simply saying something does not count as rhetoric, you have to able to use symbols, usually words, that effectively convey your meaning. Rhetoric does not need to be complicated however, it can be as simple as the word stop on a red octagon, a symbol that conveys the meaning stop or else.

Foss, Sonja K. "Contemporary Perspectives on Rhetoric."

Definitions on Google:

"The art or study of using language effectively and persuasively."

"Rhetoric." Answers.com. http://www.answers.com/topic/rhetoric


"Rhetoric is the art of speaking well."
-Quintillian

"Some Definitions of Rhetoric." Rhetoric and Composition. 2008. 17 Jun 2008 .