Definition

1. Noun:

   • The finger next to the thumb: The finger used for pointing.
   • An alphabetical listing: A list, usually at the end of a book, of names, subjects, etc., with the page numbers where they can be found.
   • A mathematical notation: A small number written above and to the right of another number, showing how many times that number is to be multiplied by itself (e.g., in 5³, 3 is the index).
   • A number or ratio representing a measurement: A figure that shows the level of something compared to a standard or previous level, often used in economics or science.
   • A numerical scale: A system for comparing different values against a fixed point.

2. Verb:

   • To adjust according to an index: To link the level of something (like wages or prices) to changes in a standard index.
   • To provide with an index: To compile an alphabetical list for a book or collection of information.
   • To list in an index: To include an item in such a list.

Usage Examples

• Noun:

  • He pointed at the map with his index.
  • Look up 'photosynthesis' in the book's index to find the correct page.
  • In the equation x², the index is 2.
  • The consumer price index is a key economic indicator.
  • The Dow Jones index tracks the performance of major US companies.

• Verb:

  • Pensions are indexed to inflation.
  • The librarian will index all the new journals this month.
  • That important concept is indexed under several different terms.

Advanced Usage

• "To index against": To adjust a value in relation to changes in another specified index.
  • The contract states that the rent will be indexed against the cost of living.

Variants and Related Words

• Indexation (n): The process of adjusting wages, taxes, etc., according to changes in a price index.
• Indexer (n): A person or program that creates an index.
• Indexical (adj): Having the nature of an index or sign.
• Index finger (n): Another term for the index.

Synonyms

• Noun: Indicator, gauge, guide, listing, catalog, exponent (mathematical).
• Verb: Catalog, list, record, adjust, link.

Related Phrases (Phrasal Verbs)

• Index to: To make an index that refers to a particular thing.
  • The database is indexed to the author's last name.

Related Idioms

• A sure index of: A reliable sign or indicator of something.
  • His nervousness was a sure index of his guilt.

Noun

1. the finger next to the thumb
2. an alphabetical listing of names and topics along with page numbers where they are discussed
3. a mathematical notation indicating the number of times a quantity is multiplied by itself
4. a number or ratio (a value on a scale of measurement) derived from a series of observed facts; can reveal relative changes as a function of time
5. a numerical scale used to compare variables with one another or with some reference number

Verb

1. adjust through indexation
   • The government indexes wages and prices
2. provide with an index
   • index the book
3. list in an index