I’ve most commonly seen those terms used in the following ways
- CTP (Community Technology Preview): Very much like “Show and Tell”. Features are present to varying degrees and customer can get an idea of where the release is going
- Beta: Features are mostly implemented but still have rough edges. Quality is fair at this point. The higher number beta, the higher the quality
- RC (Release Candidate): Product believes it’s ready to ship. One last chance for customers to provide feedback and find major blocking issues
- RTM (Release to Manufacturing): Product is complete and ready to be shipped to customers