What does a radical symbol refer to?

Answer 1

A radical symbol indicates taking a root. A radical symbol alone indicates a square root (or equivalently, raising to the 1/2 power). If there is a small superscript number just to the left of the radical, then that indicates which root to take (square root for 2, cube root for 3, forth root for 4, fifth root for five, etc). This means raising to the 1/x power, where x is the small superscript number to the left of the radical.