x^2 is "x squared."
x^3 is "x cubed."
For anything else, we use the ordinal name for the exponent.
For example, x^5 is "x to the fifth power" or, more often, "x to the fifth" for short.
x^n is "x to the nth."
Notations like x^5 are used in situations where there is no capability for mathematical typesetting. It is used casually online, in most modern computer languages, and in many spreadsheets. In typeset material, the ^ symbol would not be used, and the exponent would be written as a superscript, and set in smaller type than the letter "x."