index

/ˈɪndeks/ (bre, ipa) · /ˈɪndeks/ (ame, ipa) · /ˈin-ˌdeks/ (ame, mw) · /ˈɪn.deks/ (bre, ipa) · /ˈɪn.deks/ (ame, ipa)

index — noun

  • indexsingular
  • indexesplural

1. An ordered list, usually arranged alphabetically, of the important names, subjec

1.名詞B2
釋義

An ordered list, usually arranged alphabetically, of the important names, subjects, and topics appearing in a book or document, together with the page numbers where each item can be found.

例句

After finishing her novel, Amara created a detailed index of characters and places for her readers.

collocation: create an index

Wei checked the index at the back of the history book to find the page about the Tang dynasty.

同義詞
  • concordance

    a more detailed alphabetical list of every important word in a text, used especially for analysing literature or scripture

  • glossary

    a list of specialised terms with definitions, not page numbers

常見錯誤

❌I found the information from the index of contents.
✅I found the information in the index.
💡'table of contents' is at the front of a book; 'index' is at the back and lists specific topics alphabetically.

2. A number or system that tracks how the value, level, or performance of something

2.名詞B2
釋義

A number or system that tracks how the value, level, or performance of something changes over time, such as stock prices, the cost of living, or economic output.

例句

The consumer price index rose by three percent last year, making food and housing noticeably more expensive.

collocation: consumer price index / stock market index

Nadia compared the economic index of three Southeast Asian countries to see which one grew the fastest.

同義詞
  • indicator

    a broader term for any sign or signal of a condition; less precise than index

  • benchmark

    a fixed reference point used for comparison, not necessarily a composite number

  • gauge

    an informal measure, often approximate rather than exact

用法筆記

Often appears in compound nouns such as 'consumer price index', 'stock market index', or 'body mass index'. The preposition 'of' follows when specifying what is being measured.

3. A small figure or mark positioned above and to the right of a base number, indic

3.名詞C1
釋義

A small figure or mark positioned above and to the right of a base number, indicating how many times that base should be multiplied by itself.

例句

In the expression 2⁵ = 32, the small five above the two is called the index.

technical term: index = exponent in mathematics

The maths teacher showed the class how to add the indices when multiplying powers of the same base.

同義詞
  • exponent

    the more common term in modern mathematics for this concept

  • power

    refers to the whole operation (the base raised to the exponent)

用法筆記

In British English the plural is often 'indices' rather than 'indexes'. Common in algebra and scientific notation. The terms 'index' and 'exponent' are interchangeable in this sense.

常見錯誤

❌The index is the large number at the bottom.
✅The index is the small number written at the top right.
💡the index is the superscript, not the base.

4. The long, slender finger located beside the thumb, commonly used for pointing at

4.名詞A2
釋義

The long, slender finger located beside the thumb, commonly used for pointing at things or pressing small controls.

例句

Keiko pointed at the menu with her index finger to show the waiter which dish she wanted.

body part: index finger = the pointing finger

Guo accidentally hit his index finger with a hammer while fixing the wooden shelf in the garage.

同義詞

index — verb