Used extensively in the Manufacturing segment to describe what worked, what did not work, and how value can be added to future projects by applying what was learned about successes and failures.
See also LessonsLearnedFromFortran, LessonsLearnedInSoftwareTesting
In software development the process is often called "Post Implementation Review" (PIR). This is also the time where auditors come in to review benefits realized. One intention is to improve the accuracy of future cost estimation processes.
Not sure whether this is done much in the age of rapidly changing technology and processes. I have not seen a proper review done at my workplace since the hectic days of Y2K work.