SAP ERP (Systems, Applications and Products) is the main production developed by the german company SAP AG. ERP stands for Enterprise Resource Planning.
SAP is build up out of several individual modules which perform various organizational tasks. This modular design corresponds to the standard organizational structure in many companies.

SAP Modules
SAP Modules

The main modules are the following:
MM: Material Management
PP: Production Planning
SD: Sales and Distribution
FI: Finance
CO: Controlling
PS: Project Systems
HR: Human Resource
LE: Logistics Execution
PM: Plant Maintenance
QM: Quality Management