βῆτα

indecl., β, τό
A. the letter β, Pl. Cra. 393e, Arist. Metaph. 1087a8, AP 11.437 (Arat.), Luc. Herm. 40, etc. (Aram. bēthaā'.)
Liddell, Scott & Jones
A Greek-English Lexicon, 1940
An open-access project