What QA Server stand for?
lifecycle, testing, webserver
Solution
I only can answer half of the question. QA stands for Quality Assurance. Probably the QA server is suitable for testing, measuring the quality of the software/hardware. Probably unit tests/regression tests are meant to run on this server.
The what-you-call staging/pre-production server, is probably a system running the production code used for regular usage of the software/hardware.
Problem
For my understanding a QA Server is a testing server ... I would like to know what QA stand for and what is the difference with an Staging/Pre-Production server. Thanks for your time!