/bay"teuh/ or, esp. Brit., /bee"-/ , n.
1. the second letter of the Greek alphabet (B).
2. the consonant sound represented by this letter.
3. ( cap. ) Astron. a star that is usually the second brightest of a constellation: The second brightest star in Taurus is Beta Tauri.
4. Chem.
a. one of the possible positions of an atom or group in a compound.
b. one of two or more isomeric compounds.
5. the second of any series, as in chemistry or physics.
6. Also called beta coefficient, beta line . Stock Exchange. an arbitrary measure of the volatility of a given stock using an index of the volatility of the market as a whole: A beta of 1.1 indicates a stock that is 10 percent more volatile than the market.
7. ( cap. ) Trademark. a brand of tape format for VCR tape, incompatible with other formats. Cf. VHS .
8. Chiefly Brit. a grade showing that a student is in the middle or second of three scholastic sections in a class. Cf. alpha (def. 7), gamma (def. 9).
[ bêta beth BETH ]