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Meaning & use

index

noun, verb·Academic

Last updated

UK/ˈɪndeks/
US/ˈɪndeks/

Meanings

  1. nouncountable

    An alphabetical list at the back of a book that shows where each name or subject is mentioned.

    Grammar: Countable: one index, two indexes or indices (both plurals are used, but 'indices' is more technical).

    Patterns

    • in the index
    • look something up in the index
    • an index of something

    Check the index at the back of the book to find the topic.

    The index lists all the names mentioned in the text.

    I couldn't find 'photosynthesis' in the index.

  2. nouncountablebusinessfinance

    A number that shows how prices, wages, or other values change over time compared with a fixed point.

    Grammar: Often used in finance and economics; plural usually 'indexes' in this sense.

    Patterns

    • the consumer price index
    • a stock market index
    • rise/fall in the index

    The consumer price index rose by 2% last month.

    Investors watch the stock market index closely.

    The index of leading economic indicators fell slightly.

  3. verbtransitive

    To make a list or record of things so they can be found easily.

    Grammar: Takes an object: index the data. Often used in passive: the data is indexed.

    Patterns

    • index something
    • be indexed by something

    The librarian indexed all the new books by subject.

    The website indexes millions of pages automatically.

Word forms

pluralindexes
plural (technical)indices
third person singularindexes
past tenseindexed
past participleindexed
-ing formindexing

Common combinations

consumer price index
The consumer price index is used to measure inflation.
stock market index
The stock market index hit a new high.
index card
She wrote her notes on an index card.
index finger
He pointed with his index finger.
look up in the index
Look up the term in the index to find the page.

Synonyms and how they differ

list
A general word for a series of items; 'index' is more specific and usually alphabetical or systematic.
catalog
A complete list of items, often with details; 'index' focuses on where to find things.

Word family

indexation noun
The act of linking wages or prices to an index.

Commonly confused: index or indices vs. indexes?

index vs indices vs. indexes

Both are plurals, but 'indices' is more common in technical or financial contexts; 'indexes' is more general.

Practice

Where would you usually find an index in a book?

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