Superscript

A quantity displayed above the normal line of text (and generally in a smaller point size), as the ``$i$'' in $x^i$, is called a superscript. Superscripts are commonly used to indicate raising to a Power ($x^3$ means $x\cdot x\cdot x$ or $x$ Cubed), multiple differentiation ($f^{(3)}(x)$ is an abbreviation for $f'''(x)=d^3f/dx^3$), and a host of other operations and notations in mathematics.

See also Subscript