index

Everyday

1. An index is an alphabetical list at the back of a book that shows on which pages each topic can be found. tree →
2. An index finger is the finger next to the thumb, used for pointing. tree →
3. In maths an index (plural indices) is the small raised number that shows a power, like the 2 in 5². tree →
4. An index is also a number that shows how something changes, such as a price index. tree →
5. To index something means to make an index for it or list it in order. tree →

In the lessons

In school pupils use the index of a non-fiction book to find information fast; it is a key research skill together with the contents page and the glossary. In maths «index» or «indices» is the UK word for powers (exponents): 2³ means 2 × 2 × 2 = 8. Phrases: «look it up in the index», «index finger», «laws of indices», «index card».

Examples

• Look in the index to find the page about volcanoes. tree →
• The index is at the back; the contents page is at the front. tree →
• Point with your index finger. tree →
• In 3⁴, the index is 4, so it means 3 × 3 × 3 × 3. tree →
• We learned the laws of indices in maths. tree →
• The teacher wrote the questions on index cards. tree →
• The library computer indexes every book by title and author. tree →
• The words in an index are in alphabetical order. tree →
• Page 384--page reference 194 amended to 201 in index entry for "Mythology, &c. tree →

Note

Plurals: «indexes» for book lists, «indices» often in maths and science. In the USA «exponent» is more common than «index» for powers. Trap: the contents page lists chapters in page order; the index lists topics in alphabetical order. In maths problems, the index tells how many times to multiply the base by itself, not to multiply by the index (3² = 9, not 6).

In Jewish tradition

In school pupils use the index of a non-fiction book to find information fast; it is a key research skill together with the contents page and the glossary. In maths «index» or «indices» is the UK word for powers (exponents): 2³ means 2 × 2 × 2 = 8. Phrases: «look it up in the index», «index finger», «laws of indices», «index card».

Examples

• Source: https://en.wikisource.org/wiki/SepherYetzirah (/Preface, /Introduction, /SepherYetzirah), fetched via index.php?action=render on 2026-10-17. (Sefer Yetzirah, Westcott 1893) tree →
• PARTIAL: English Wikisource transcription (proofread from Index:Sepher Yetzirah.djvu) — only Preface to the Second Edition, Introduction, and the text (chapters I-VI). (Sefer Yetzirah, Westcott 1893) tree →
• Contains Kalisch's pointed Hebrew text (his base text), English translation, preface, notes, glossary. (sacred-texts site errata page not included; Hare's attribution notice kept as in etext.) Source: Internet Sacred Text Archive, https://archive.sacred-texts.com/jud/sy/index.htm (etext by J. (Sefer Yetzirah, Kalisch 1877) tree →

Note

Plurals: «indexes» for book lists, «indices» often in maths and science. In the USA «exponent» is more common than «index» for powers. Trap: the contents page lists chapters in page order; the index lists topics in alphabetical order. In maths problems, the index tells how many times to multiply the base by itself, not to multiply by the index (3² = 9, not 6).