EnterpriseResourcePlanning is better known by its acronym of ERP.
These are more or less integrated business systems across multiple business processes, e.g.
OrderToCash? RequisitionToSettle? CloseAndReporting? SupplyDemand? EmployeeServices?
and the interconnections among them.
Examples include SapRthree?, PeopleSoft, and MicroSoftGreatPlains?, MicroSoftNaviSoft?, and Oracle (acquired PeopleSoft and Siebel).
What relationships exist between ERP and CustomerRelationshipManagement (CRM) and SupplyChainManagement (SCM)?
Historically, no. Currently, yes. ERP started as a re-marketing of MRPII, which was a combination of Material Requirements Planning (MRP) and customer orders, purchase orders and traditional accounting modules (Accounts Payable and Receivable, Payroll and General Ledger).
The first commercial software called ERP was the same software that was called MRPII in the previous marketing materials. It was inwardly-focused (on a single company's resources), as was MRPII.
CRM and SCM evolved as separate add-on software products because of weaknesses in ERP software in dealing with outwardly-focused customer and supplier relationships. For example, Siebel for CRM and i2 and Manugistics for SCM.
Later, each ERP software vendor either purchased or developed their own CRM and SCM modules, sometimes only weakly integrated with their other modules.
As a result of all of this development-by-accretion, most ERP systems have many programs that essentially do the same things. For example, planning and scheduling: MRP, Master Production Scheduling (MPS), Distribution Requirements Planning (DRP), the planning features of SCM, Advanced Planning and Scheduling (APS), and the scheduling features of Manufacturing Execution Systems (MES). Likewise, CRM duplicates features of Order Management and Accounts Receivable.