Enterprise resource planning (ERP) is defined as the ability to deliver an integrated suite of business applications. ERP tools share a common process and data model, covering broad and deep operational end-to-end processes, such as those found in finance, HR, distribution, manufacturing, service and the supply chain.
http://www.gartner.com/it-glossary/enterprise-resource-planning-erp/
However, the key question to be answered are as follows:
1) Whether ERP should be treated as a software or a strategy??
2) Should ERP implementation be in the hands of technical team or it should be owned by CXO??
3) What should be the role of business managers??
