Wiktionary
n. (context computer technology English) A development status that usually means an early version of a program or application, that is most likely unstable, but is useful to show what the product will do to, usually, a selected group. Sometimes this stage is referred to as a preview version. Sometimes no more features are added after this release, but bug fixes continue. This release comes after a pre-alpha version and before a beta version. As opposed to a beta version an alpha version is usually not feature complete.
Usage examples of "alpha version".
He found an alpha version of a WWII submarine simulator with superb graphics called War Patrol, designed by Gordon Walton, and became impervious to human contact for half a day, happily stalking defenseless convoys and torpedoing hospital ships.