Definition of Index
Quick Meaning of Index
A list at the back of a book showing where to find topics. Or a number that measures change or comparison (like the stock market index).
Detailed Definition of Index
An alphabetical list of topics, names, or references with page numbers, usually at the end of a book; or a number or ratio that shows relative changes or levels in a series.
How to Pronounce Index
Stress pattern: Oo (2-syllable word).
Tip: Stress the first syllable: IN-deks. Simple two-syllable word; first syllable is clearly stressed.
Watch out: Learners rarely mispronounce this, but some stress both syllables equally (IN-DEX). Correct: stressed first only (IN-deks).
Origin and Etymology of Index
From Latin 'index' (informer, sign). 'In-' (into) + 'dicere' (to say/point out). Originally meant 'one who points out'. Entered English in 14th century.
How to Use Index in a Sentence
Each example shows “index” with a CEFR level so learners can pick examples that match their fluency.
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“The index at the end of the textbook helped students find specific topics quickly.”
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“The stock market index rose by 2 percent this week.”
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“The Consumer Price Index is used to measure inflation.”
Synonyms and Antonyms of Index
Common Synonyms for Index
Smart Synonyms for Index — When to Use Each
- indicator
- Emphasizes measuring or showing change; statistical context
- list
- More general; any organized collection of items
- catalogue
- Complete organized listing; more formal than 'list'
Common Collocations with Index
These phrases pair with “index” in everyday English:
- stock index
- price index
- index finger
- book index
- index value
Common Mistakes When Using Index
Even fluent speakers slip up with “index”. Here’s how to avoid the most common errors:
- ✗ Wrong: Look at the indices at the back of the book.
- ✓ Correct: Look at the index at the back of the book.
- Why: For the book's reference list, use singular 'index'. 'Indices' is plural but less common in everyday use; 'indexes' is more standard.
- ✗ Wrong: The economy index increased significantly.
- ✓ Correct: The economy index increased. / The economic index increased.
- Why: Use 'economic' (adjective) not 'economy' (noun) before 'index'. Say 'economic index' or add article: 'the index of the economy'.
- ✗ Wrong: This index shows us how much the prices change.
- ✓ Correct: This index shows how much prices have changed. / This index indicates price changes.
- Why: Awkward phrasing; tighten to 'shows how much prices have changed' or use 'indicates'.
Words Confused With Index
- Index vs Indicator: 'Indicator' is only a noun (something that shows). 'Index' can be noun or verb, and has specific meanings in statistics/reference.
Other Forms of Index
Frequently Asked Questions About Index
What is the meaning of "Index"?
A list at the back of a book showing where to find topics. Or a number that measures change or comparison (like the stock market index).
How do you pronounce "Index"?
The IPA is /ˈɪndeks/. Stress the first syllable: IN-deks. Simple two-syllable word; first syllable is clearly stressed.
What part of speech is "Index"?
"Index" is a noun at B2 level (Common European Framework).
What are synonyms for "Index"?
Common synonyms include list, catalogue, register.
How do you use "Index" in a sentence?
For example: "The index at the end of the textbook helped students find specific topics quickly."