Rational Expression: Made up of polynomials, usually in the form of a fraction (i.e. (x2 - 4)/(x))
Polynomial: The word means "many terms," so it is an expression made up of many terms, either added, subtracted, or multiplied together. Once you start dividing terms, you have a rational expression!
A nice commentary on how to deal with division and multiplication of rational expressions. For help on simplifying rational expressions, see Nate Muckley's packet.
