an alphabetical list of names, subjects, etc. with reference to the places where they occur, typically found at the end of a book, a number or ratio that represents a property or quantity's relation to another property or quantity, a statistical measure of the change in an economy or a stock market

to be off the index, to put something on the index, to have something on the index finger

index card, index of suspicion, cost-of-living index

Formal and Informal Expressions of index

In different contexts, you can replace 'index' with suitable alternatives. In a more formal setting, 'catalogue, register' is apt. In informal speech or writing, 'list, directory' is a commonplace synonym.

index: Explore its Definition & Usage

index Definition

1an alphabetical list of names, subjects, etc. with reference to the places where they occur, typically found at the end of a book
2a number or ratio that represents a property or quantity's relation to another property or quantity
3a statistical measure of the change in an economy or a stock market

Using index: Examples

Take a moment to familiarize yourself with how "index" can be used in various situations through the following examples!

Example
I found the term in the index at the back of the book.
Example
The consumer price index rose by 2% last year.
Example
The Dow Jones Industrial Average is an index of 30 major American companies.
Example
The index finger is usually the most dexterous and sensitive of the fingers.

index Synonyms and Antonyms

Synonyms for index

Antonyms for index

Idioms Using index

to be off the index
to be excluded from a list or catalog
Example
The product was taken off the index due to safety concerns.
to put something on the index
to add something to a list or catalog
Example
The library put the new book on the index of recommended reads.
to have something on the index finger
to wear a ring on the index finger, typically the finger next to the thumb
Example
She proudly wore her wedding ring on her index finger.

Phrases with index

index card
a small card with lines on which information can be written
Example
I wrote down her phone number on an index card.
index of suspicion
the level of concern a physician has for a particular disease or condition based on the patient's symptoms and medical history
Example
The doctor had a high index of suspicion for cancer given the patient's family history.
cost-of-living index
a measure of the changes in the cost of basic necessities such as food, housing, and clothing over time
Example
The cost-of-living index in this city is higher than the national average.

Origins of index

from Latin 'indicare', meaning 'to point out'

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Summary: index in Brief

The term 'index' [ˈɪndeks] refers to a list of names or subjects with references to their locations, a numerical or statistical measure of a property's relation to another, or a statistical measure of economic or stock market changes. Examples include 'I found the term in the index at the back of the book,' and 'The consumer price index rose by 2% last year.' Phrases like 'index card' and idioms like 'to put something on the index' extend its usage.