Definition of Index 1. A numerical scale used to compare variables with one another or with some reference number Noun 2. A number or ratio (a value on a scale of measurement) derived from a series of observed facts; can reveal relative changes as a function of time Noun 3. A mathematical notation indicating the number of times a quantity is multiplied by itself Noun 4. An alphabetical listing of names and topics along with page numbers where they are discussed Noun 5. The finger next to the thumb Noun 6. List in an index Verb 7. Provide with an index Verb 8. Adjust through indexation Verb Morphology of "index" Synonyms for word "index" Semanticaly linked words with "index" Hyponims for word "index" Lexical Analysis for "index" indexical of or relating to or serving as an index indexer someone who provides an index someone who provides an index indexing the act of classifying and providing an index in order to make items easier to retrieve indexation a system of economic regulation: wages and interest are tied to the cost-of-living index in order to reduce the effects of inflation etymology Rolodex etymology Soundex etymology coindex etymology deindex etymology humidex etymology indexable etymology indexation etymology indexical etymology indexless etymology indexlike etymology reindex etymologically related indicate etymologically related indication etymologically related indicator etymologically related indicia etymological origin of index [Latin] is derived from index locorum is derived from index nominum is derived from index rerum is derived from index term is derived from index verborum is derived from indexed is derived from indexer is derived from indexes is derived from indexical is derived from indexing is derived from indexless is derived from price index is derived from refractive index