an alphabetical list of names, subjects, etc., with references to the places where they occur, typically found at the end of a book.
Endnotes, bibliography, and an index of names and subjects facilitate scholarly use and quick reference.
an indicator, sign, or measure of something.
exam results may serve as an index of the teacher's effectiveness
an exponent or other superscript or subscript number appended to a quantity.
The thesis contains a proof of the fact that for any closed manifold the sum of the indices of a generic vector field is a topological invariant, namely the Euler characteristic.
a symbol shaped like a pointing hand, typically used to draw attention to a note.