Terminology-O

Terminology… O

Obsolete forms

Also known as obsolete subdivisions, an obsolete form or subdivision is a subdivision no longer used by current MARC21 standards. An example of an obsolete form would be the topical heading Nurses and nursing. This heading is no longer used and is replace by two distinct topical headings, 650 0$a Nurses and 650 0$aNursing. (mpg)

OCLC Institution Code

Participating libraries using the OCLC Union Catalog are issued an coded Symbol unique to their library. The symbol is usually a three to five digit code represented by letters and other characters. (ac)

Ontology

In both computer science and information science, an ontology is a formal representation of a set of concepts within a domain and the relationships between those concepts. It is used to reason about the properties of that domain, and may be used to define the domain. Ontologies are used in artificial intelligence, the Semantic Web, software engineering, biomedical informatics, library science, and information architecture as a form of knowledge representation about the world or some part of it. Common components of ontologies include: Most ontologies describe individuals (instances), classes (concepts), attributes, and relations. (wp)

OPAC

An Online Public Access Catalog or OPAC (aka iPAC for Internet/Intranet Public Access Catalogue) is a computerized online catalog of the materials held in a library, or library system. The library staff and the public can usually access it at computers within the library, or from home. OPAC terminals began to replace card catalogs in many libraries in the 1980s. Since the mid-1990s, these systems have increasingly migrated to Web-based interfaces. OPACs are often part of an integrated library system. (wp)