- 1 (pl. indexes) a list of names or topics that are referred to in a book, etc., usually arranged at the end of a book in alphabetical order or listed in a separate file or book Look it up in the index. Author and subject indexes are available on a library database. See related entries: Parts of a book
- 2(British English) = card index
(indexes, indices BrE BrE//ˈɪndɪsiːz//; NAmE NAmE//ˈɪndɪsiːz//) a system that shows the level of prices and wages, etc. so that they can be compared with those of a previous date the cost-of-living index The Dow Jones index fell 15 points this morning. stock-market indices house price indexes See related entries: Economy
- 4(indices BrE BrE//ˈɪndɪsiːz//; NAmE NAmE//ˈɪndɪsiːz//) a sign or measure that something else can be judged by The number of new houses being built is a good index of a country's prosperity.
- 5 (also indices [plural]) (mathematics) the small number written above a larger number to show how many times that number must be multiplied by itself. In the equation 42 = 16, the number 2 is an index. See related entries: Mathematical terminology Word Origin late Middle English: from Latin index, indic-