ALL meanings of online public access catalog
- noun Technical meaning of online public access catalog (library) (OPAC) A computerised system to catalogue and organise materials in a library (the kind that contains books). OPACs have replaced card-based catalogues in many libraries. An OPAC is available to library users (public access). 1
- noun online public access catalog (library science) A computerized online publicly accessible catalog of the materials held in a library, or library system. 0