Webster's Revised Unabridged Dictionary · 1913

Beta

Beta , noun

[Greek bh^ta.]

Beta (B, β) is used variously for classifying, as: (a) (Astronomy) To designate some bright star, usually the second brightest, of a constellation, as, β Auriga. (b) (Chemistry) To distinguish one of two or more isomers; also, to indicate the position of substituting atoms or groups in certain compounds; as, β-naphthol. With acids, it commonly indicates that the substituent is in union with the carbon atom next to that to which the carboxyl group is attached.

(Astronomy) The second letter of the Greek alphabet, B, β. See B, and compare etymology of Alphabet.