/ ˈɪndeks; NAmE / noun , verb
■ noun
1.
( pl. in·dexes ) 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.
2.
( BrE ) = card index
3.
( pl. in·dexes or in·dices / ˈɪndɪsiːz; NAmE /) 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
4.
( pl. in·dices /ˈɪndɪsiːz/) a sign or measure that sth else can be judged by :
The number of new houses being built is a good index of a country's prosperity.
5.
(usually indices [pl.] ) ( mathematics ) the small number written above a larger number to show how many times that number must be multiplied by itself. In the equation 4 2 = 16, the number 2 is an index.
■ verb [ vn ]
1.
to make an index of documents, the contents of a book, etc.; to add sth to a list of this type :
All publications are indexed by subject and title.
2.
[ usually passive ] index sth (to sth) to link wages, etc. to the level of prices of food, clothing, etc. so that they both increase at the same rate
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WORD ORIGIN
late Middle English : from Latin index , indic- forefinger, informer, sign, from in- towards + a second element related to dicere say or dicare make known; compare with indicate . The original sense index finger (with which one points), came to mean pointer (late 16th cent.), and figuratively something that serves to point to a fact or conclusion; hence a list of topics in a book (“pointing” to their location).