A "beta version" is the first version released outside the organization or community that develops the software, for the purpose of evaluation or real-world testing. The process of delivering a beta version to the users is called beta release. Beta level software generally includes all features, but may also include known issues and bugs of a less serious variety.

Read more on the GS-911 Release cycle in the FAQ: "How does your Release Cycle work?".

For a more detailed description on software release cycles in general and Beta releases in particular, please see the Wikipedia definition.