Beta software is usually feature complete,
but may have known limitations or bugs. Betas are either closed (private) and
limited to a specific set of users, or they can be open to the general public.
CTP stands for Community Technology
RTM stands for Released to Manufacturing
and is a throwback to the days when software was mostly released as CDs.
RTW is a related term that stands for
Released to Web which is more descriptive of how software is actually shipped
Service pack (SP) is simply an RTM (or RTW)
release of fixes and/or improvements to some software. Service pack tends to
include all the hotfixes and patches released since the product originally was