GIS, like all disciplines, utilizes a wide range of terms and abbreviations, many of which have well-understood and recognized meanings. For a large number of commonly used terms online dictionaries have been developed, for example: those created by the Association for Geographic Information (AGI); the Open Geospatial Consortium (OGC); and by various software suppliers. The latter includes many terms and definitions that are particular to specific products, but remain a valuable resource. The University of California maintains an online dictionary of abbreviations and acronyms used in GIS, cartography and remote sensing. Web site details for each of these are provided at the end of this Guide.