Definition: Commonly used to refer to software, beta is a not-quite-finalized version. Software goes through an alpha stage that may include internal testing among employees. Then the beta version of the software may be released as a beta test to a limited number of people in and outside of the company in order to get feedback on functionality and any bugs that still need fixing before releasing a final version on the market.
When a company sells a final version of a program that appears to have a lot of problems and deficiencies, users will often accuse them of selling beta software -- that is, releasing a program that hasn't been thoroughly tested and fully developed.
