Definition:Square Root

Definition
A square root of a number $n$ is a number $z$ such that $z$ squared equals $n$.

Also known as
Because square roots (and in particular, positive square roots) are so much more commonly encountered in mathematics than any other sort of root, $\sqrt x$ is frequently just called root $x$

In translations of, the word side can be found, often in quotes to emphasise the awkward nature of the language available to the Ancient Greeks.