Name given to a numerical ou algebraic expression expressed using the symbol $$\sqrt{\hphantom{9}}$$ or $$\sqrt[n]{\hphantom{9}}$$.

### Educational notes

• The $$\sqrt{\hphantom{9}}$$ symbol is also called a “radical”, but has no meaning on its own.
• The $$\sqrt{\hphantom{9}}$$ symbol is read as “radical” or “positive square root of…”
• In the expression $$\sqrt[n]{\hphantom{9}}$$, the number $$n$$ is called the index of the radical; the expression is called a radical of order $$n$$.
The horizontal bar that groups the radicand is called the vinculum.
• Similar radicals are radicals with the same index or the same order.
• Christoff Rudolff is credited with having introduced the radical symbol.