Index
Small number to the lower right of the letter it characterizes and that is generally used to number it.
- It is important not to confuse the terms "index" and "exponent", since "[latex]x_{2}[/latex]" is read as "[latex]x[/latex] index 2" and "[latex]{x}^{2}[/latex]" is read as "x exponent 2".
- There is also the index of a radical; in the expression [latex]\sqrt[3]{27}[/latex], the number 3 is the index of the radical. When the radical does not have an index, as in [latex]\sqrt{27}[/latex], the index of the radical is understood to be 2.