index
US /ˈɪn.deks/
UK /ˈɪn.deks/

1.
an alphabetical list of names, subjects, etc., with references to the places where they occur, typically found at the end of a book or periodical
:
•
Look up the topic in the index at the back of the book.
•
The report includes a comprehensive index of all cited sources.
2.
3.
a pointer or indicator, especially the forefinger
:
•
He pointed with his index finger.
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The index of the machine indicates the current pressure.
1.