Beta (Β β) is the 2nd letter of the Greek alphabet and has a numeric value of 2. Beta should not be confused with a similar-looking but unrelated letter in German language orthography, ß.
In software development, a "beta version" of a product is one that is still in development but is published for testing purpose. See development stage.
... stations once served by the Metropolitan Line, District Line or Northern City Line (Great Northern & City Railway) remain open as mainline stations:
Great ...