I couldn't find the information I needed, so I checked the index of the book.

The indexer is responsible for creating and maintaining the index of the database.

The book includes a cross-index for easy reference.

I pointed at the map with my index finger.

The stock market index reached a new high today.

The index of refraction determines how much a ray of light bends when it passes from one medium to another.

I use the thumb index to quickly find the page I need in the dictionary.

The cephalic index is a measurement used in anthropology to determine the shape of the head.