An '''abstracting service''' is a service that provides [[abstractAbstract (summary)|abstracts]]s of publications, often on a subject or group of related subjects, usually on a subscription basis.<ref>Manzer, B. M. (1977). ''The Abstract Journal, 1790-1920. Origin, Development and Diffusion''. Metuchen, N.J.: The Scarecrow Press.</ref> An '''indexing service''' is a service that assigns descriptors and other kinds of access points to [[document]]s. The word indexing service is today mostly used for computer programs, but may also cover services providing [[back-of-the-book index]]es, journal indexes, and related kinds of indexes (see [[index (publishing)]]. An '''indexing and abstracting service''' is a service that provides shortening or summarizing of documents and assigning of descriptors for referencing documents.<ref>Klempner, Irving M. (1968). ''Diffusion of abstracting and indexing services for government-sponsored research''. Metuchen, N.J. Scarecrow Press.</ref>
The product is often an '''abstract journal''' or a [[bibliographic index]], which may be a subject bibliography or a [[bibliographic database]].
