Die Begriffe Concurrent und Simultaneous Engineering werden in den meisten Fällen synonym verwendet. Hier eine der gebräuchlichsten Definitionen nach Pennel und Winner:

„Concurrent Engineering is a systematic approach to the integrated, concurrent design of products and their related processes, including manufacture and support. This approach is intended to cause the developers, from the outset, to consider all elements of the product life cycle from conception through disposal, including quality, cost, schedule, and user requirements.“

(Pennel, J.P ; Winner, R.I: Concurrent Engineering: Practices & Prospects. Institute for Defense Analyses. IEEE Global Telecommunications Conference and Exhibition Part 1. 27-30 Nov 1989, S. 647-655.)