used to indicate a root is called a radical, or sometimes a surd.
is therefore read "
radical ," or "the nth
root of ."
In the radical symbol, the horizonal line is called the vinculum,
the quantity under the vinculum is called the radicand,
and the quantity
written to the left is called the index.
In general, the use of roots is equivalent to the use of fractional exponents
as indicated by the identity