beta

UK: /ˈbiːtə/ US: /ˈbeɪtə/ ,(bā′tə or, esp. Brit., bē′-)

WordReference Random House Learner's Dictionary of American English © 2025

be•ta /ˈbeɪtə/   n. [countable] , pl. -tas. 

1. Linguistics the second letter of the Greek alphabet (B, &bgr;).

WordReference Random House Unabridged Dictionary of American English © 2025

be•ta  (bā′tə or, esp. Brit., bē′-), n. 

1. Linguistics the second letter of the Greek alphabet (β, B).
2. Linguistics 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. Chemistry
   • one of the possible positions of an atom or group in a compound.
   • one of two or more isomeric compounds.
5. Chemistry, Physics the second of any series, as in chemistry or physics.
6. Stock Exchange, Business Also called beta coefficient, beta line. 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. Radio and Television, Trademarks (cap.) [Trademark.] a brand of tape format for VCR tape, incompatible with other formats. Cf. VHS.
8. British Terms, Education [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).

• Semitic; compare Hebrew bēth beth
• Greek bêta
• Latin

Collins Concise English Dictionary © HarperCollins Publishers::

beta / ˈbiːtə/ noun

1. the second letter in the Greek alphabet (Β, β), a consonant, transliterated as b
2. the second highest grade or mark, as in an examination
3. (modifier) denoting a passive or submissive person or animal within a group: a beta male

Etymology: from Greek bēta, from Hebrew; see beth