It's a term for a videogame, often close to it's release date, getting into a public beta phase in which one may pay the full price to download and play it through a unstable, and highly unsecure launcher.
Most often that does not include a key for a gaming plattform like Steam, Uplay, Origin, Battle.net etc., at it's full release and must then be bought again.
Have you heared? Metro Exodus gone Epic Games for another year!