The radical symbol by itself is used in math to represent taking the square root of an expression. It is also used to represent taking the nth-root of a number when a number is place above the start of the symbol. Typically the radical symbol is used in an expression like this:

\sqrt{4}

In plain language, this means take the square root of the number four. Shown below are various computer formats for the radical symbol.

Symbol Format Data
Unicode
8730

TeX
\sqrt{}
SVG