Refers to an alphabetical or topical list of terms with page numbers, typically at the back of a book or document.
Please look it up in the index of this book.
It took time to create the index.
It took half a year to compile the index for this dictionary.
I looked up the meaning of the word using the index.
If there's a term you don't understand, please look it up in the index.
That person's name appears in the index.
name index; index of persons
citation index