beta

beta /bay't*/, /be't*/ or (Commonwealth) /bee't*/ n. 
   1. Mostly working, but still under test; usu. used with `in': `in
   beta'.  In the {Real World}, systems (hardware or software)
   software often go through two stages of release testing: Alpha
   (in-house) and Beta (out-house?).  Beta releases are generally made
   to a small number of lucky (or unlucky), trusted customers.
   2. Anything that is new and experimental.  "His girlfriend is in
   beta" means that he is still testing for compatibility and
   reserving judgment.  3. Flaky; dubious; suspect (since beta
   software is notoriously buggy).

   Historical note: More formally, to beta-test is to test a
   pre-release (potentially unreliable) version of a piece of software
   by making it available to selected customers and users.  This term
   derives from early 1960s terminology for product cycle checkpoints,
   first used at IBM but later standard throughout the industry.
   `Alpha Test' was the unit, module, or component test phase; `Beta
   Test' was initial system test.  These themselves came from earlier
   A- and B-tests for hardware.  The A-test was a feasibility and
   manufacturability evaluation done before any commitment to design
   and development.  The B-test was a demonstration that the
   engineering model functioned as specified.  The C-test
   (corresponding to today's beta) was the B-test performed on early
   samples of the production design.