Hello,
Rational algebraic expression is a term found in mathematics. It is used to describe any equation that involves any form of algebraic operation. This can include adding, subtracting, multiplying and dividing, so long as it includes a rational number as it's exponent.
The definition of a rational number is "Any number that can be made by dividing one integer by another" according to mathsisfun.com So combining this concept with an algebraic operation would be referred to as a 'rational algebraic expression."
Further, any operation that is considered an algebraic expression, that includes the outcome of two other algebraic expressions, will be a rational algebraic expression by default. For example, if X and Z are algebraic expressions, then X over Z is a rational algebraic expression.
I hope this answers your question.