(originally called Index Server) a Windows service that maintained an index of most of the files on a computer to improve searching performance on PCs and corporate computer networks.
(information science) The act of describing a document by index terms to indicate what the document is about or to summarize its content, the index terms often coming from a controlled vocabulary.
(information science) A controlled set of terms selected from natural language and used to represent, in summary form, the subjects of documents within a given field of knowledge.