olemus
(a) indeksi loomise ja hoolduse vahend
Wiktionary:
1. a person or program which creates indexes

(b) objektprogrammeerimisel:
mingi klassi isendite indekseerimise vahend
Wiktionary:
2. (computing, programming, .NET) a special property of a class allowing objects of the class to be accessed by index as though they were arrays or hash tables
https://en.wikipedia.org/wiki/Indexer_(programming)