index

noun

1.
a numerical scale used to compare variables with one another or with some reference number
Derived from:
index
2.
a number or ratio (a value on a scale of measurement) derived from a series of observed facts; can reveal relative changes as a function of time
3.
a mathematical notation indicating the number of times a quantity is multiplied by itself
4.
an alphabetical listing of names and topics along with page numbers where they are discussed
Derived from:
index indexical