GIS applications cross all disciplines. Some common GIS applications are in the areas of:
To learn more about GIS and how it is used, try the following web sites:
USGS What is GIS?
USGS web site providing definitions, descriptions of how GIS works and how it is used.
Additional GIS Definitions from the Census Department
U.S. Census site with some definitions and frequently asked questions about GIS and it's uses.
Dictionary of Abbreviations and Acronyms in Geographic Information Systems, Cartography, and Remote Sensing
Dictionary from U.C. Berkley which decodes abbreviations and acronyms found in various publications including maps and websites.
AGI GIS Dictionary
Dictionary of GIS terms from the Association of Geographic Information, a multidisciplinary organization dedicated to the advancement of the use of geographically related information.