# Why is x^-3 not a Exponential Function?

The definitions are distinctly clear. ${a}^{x}$ is an exponential function and ${x}^{a}$ is a power function.
${a}^{x}$ is defined as an exponential function. Examples are $10$x, 2^x and e^x#
${x}^{a}$ is defined as a power function. Examples are ${x}^{2} , {x}^{\frac{1}{2}} \mathmr{and} {x}^{- 3}$.