With GIS you can track characteristics, or attributes, of things and events. But what makes GIS different from other information systems is the ability to link that information to where those things exist or events occur. You can also layer that location data to give you a better understanding of how it all works together. You choose what layers to combine based on what questions you need to answer.
Browse the following websites for more information:
- Esri - What is GIS?
- National Geographic Eduction - GIS
- GIS Lounge - What is GIS?
- Wikipedia - Geograhic Information System