See radical for other uses of the term
In mathematics, the n-th root or radical of the non-negative real number a, written as , is the unique non-negative real number b such that bn=a. See square root for the case where n=2.

Operations with radicals are given by the following formulas:

where a and b are positive.

To every non-zero complex number a there are n different complex numbers b such that bn = a, so the symbol cannot be used unambiguously. The n-th roots of unity are of particular importance.