This is a wikification of Phab:T123753#2494495
Definitions for each of these as I understand them:
- "Incident report" - this is the longstanding process that Ops has after downtime or other problematic event on the Wikimedia cluster
- "w:Retrospective" - a meeting often used by teams involved in some form of w:agile software development, typically held at the end of a project, a sprint, or an iteration of some variety.
- "Postmortem" - frequently used by way of analogy, as of this writing, this word redirects to "autopsy" on enwiki (as does "Post-mortem"). However, w:Post-mortem (disambiguation) offers somewhat more helpful content, but I've usually heard "postmortem" used to describe "let's analyze what happened after something went very wrong" (like an "incident report") rather than generically "an after project assessment".
- "w:Hotwash" - a nicer analogy than postmortem, and a term that is also in pretty widespread use. Much of my approach to running retrospective meetings comes from someone who prefers to call them "hot washes".
I've been avoiding the postmortem analogy because ... ewww. ;-) I've also been guilty of using "retrospective" and "incident report" interchangeably.
Even more confusing, there's a matrix here:
|Incident||(no name, usually part of some other meeting)||Incident report|
|Retrospective||Retrospective meeting||Retrospective report|
|Postmortem||Postmortem meeting||w:Postmortem documentation|
|Hotwash||w:Hotwash||After action review|