There also exist two levels of ArcGIS Enterprise–ArcGIS Enterprise and ArcGIS Enterprise Workgroup.
The ArcGIS Enterprise level is designed for medium to large-sized teams. At this level, enterprise geodatabases are utilized with ArcGIS Enterprise allowing an unlimited number of simultaneous connections to the database. This level comes with one four-core processor license and is scalable with additional two-core add-on packs.
The ArcGIS Enterprise Workgroup level is designed for smaller teams and organizations, allowing a maximum of 10 simultaneous connections to workgroup and file geodatabases; enterprise geodatabases are not supported. The base ArcGIS Enterprise deployment (Server, Portal, Web Adaptor, or Data Store) must be deployed all in one on a single machine with up to four cores. Server roles have a maximum of four cores–no add-on two-core packs are available.
ArcGIS GIS Server Basic edition includes geodatabase management and the ability to publish read-only feature services. Also included are the geodata service and geometry service. Web editing is not available and this edition cannot be federated with Portal for ArcGIS. No ArcGIS Server extensions are available for purchase and implementation at the Basic edition.
This manages your geodatabase and public feature services (without the ability to edit); it cannot be deployed with Portal for ArcGIS.