From Longman Dictionary of Contemporary Englishindexin‧dex1 /ˈɪndeks/ ●●○ W2 AWL noun [countable] 1 (plural indexes)TCNLIST an alphabetical list of names, subjects etc at the back of a book, with the numbers of the pages where they can be found2 (plural indexes)TC a set of cards or a database containing information, usually arranged in alphabetical order and used especially in a library3 (plural indices /ˈɪndəsiːz/)SIGN/INDICATION a standard by which the level of something can be judged or measuredindex of The changing size of an infant’s head is considered an index of brain growth.4 (plural indices /ˈɪndəsiːz/ or indexes) technicalBBT a system by which prices, costs etc can be compared to those of a previous date
Examples from the Corpusindex• The changing size of an infant's head is considered an index of brain growth.• The Nasdaq composite index slumped 20. 33 points, or 1. 2 percent, at 1,650. 92.• The Philadelphia Fed said its general economic index fell to negative 16. 6 for January from 11. 3 in December.• The Dow Jones index surged 47.63 points in late trading to close at 3353.76 having risen by 124 points in four sessions.• The forward market index fell 73.25 to 6,589.07.• Look under B in the index to see if biology is covered in the book.• It's a lot quicker if you use the index.• An example of this index page is shown in figure 6.2.• Telecom and smelting shares pulled down the broader Topix index of all shares on the first section of the Tokyo Stock Exchange.• The Topix index lost 1. 79, or 0. 11 percent, to 1,585. 52.• That is rarer still for a worldwide index.