A software-based system that provides a link between planning and administrative systems and the shop floor. It can link MRP II-generated production schedules to direct process-control software. An element of computer-integrated manufacturing, MES encompasses such functions as planning and scheduling, production tracking and monitoring, equipment control, maintaining product histories (verifying and recording activities at each stage of prodution), and quality management. 

Tip excerpted from: The Professional's Guide to Maintenance and Reliability Terminology by Ramesh Gulati, Jerry Kahn and Robert Baldwin