(1) A significant point or event in the project. (PMI 2008)
(2) A scheduled event used to measure progress. (IEEE 1998)
(1) PMI. 2008. A Guide to the Project Management Body of Knowledge (PMBOK® Guide), 4th ed. Newtown Square, PA, USA: Project Management Institute (PMI).
(2) IEEE. 1998. IEEE Standard for Software Project Management Plans. New York, NY, USA: Institute of Electrical and Electronics Engineers Inc.