ArcPy is composed of a number of modules:

• arcpy — the basic functions and geoprocessing tools
• arcpy.mapping — access to mapping and map document tools
• arcpy.da — a data access module for working with feature classes and tables
• arcpy.sa — the Spatial Analyst extension module
• arcpy.na — the Network Analyst extension module

Note: Some of these modules require additional licensing from Esri.

These can be imported all at once (import arcpy) or individually (import arcpy.sa as sa)