ArcGIS Server editions
ArcGIS Server offers a scalable line of server product editions built on a common set of technology components that are distinguished by both functionality and capacity.
The functionality in ArcGIS Server is provided via three different editions: Basic, Standard, and Advanced.
Each of these three functional editions is provided at two separate levels, scaled according to capacity. These two levels are Workgroup and Enterprise.
To view a functionality matrix describing which features are available at each edition and level, see the ArcGIS Server literature page on the ESRI Web site.