But this web definition just happens to be real-world correct.
Wiki is by no mean authoritative.
I've been in the software development game for longer than I care to
remember. And the stages of software generally are:
Alpha: Developper makes sure that the code compiles and that a careful
run through (Good Code Path) does not blow up.
Beta: While features are still beiong worked on, the software is released
to a larger group of testers to run on a larger set of configuration
RC1 to RCn: No new features are being worked on. This is the software as
the developper will release it. A large group of testers are asked to use
it to discover as many remaining bugs as possible.
RTM: The developper has deemed that the point of dimishing return with
regards to fixing bugs has been reached. The software will be released as
a supported entity.
SP1 to SPn: Additional bugs are fixed and additional features may be
introduced.
RC software is still under development. Use at your own risk.