Try Our Apps


Avoid these words. Seriously.


[bey-tuh or, esp. British, bee-] /ˈbeɪ tə or, esp. British, ˈbi-/
the second letter of the Greek alphabet (β, B).
the consonant sound represented by this letter.
(initial capital letter) Astronomy. a star that is usually the second brightest of a constellation:
The second brightest star in Taurus is Beta Tauri.
  1. one of the possible positions of an atom or group in a compound.
  2. one of two or more isomeric compounds.
the second of any series, as in chemistry or physics.
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.
(initial capital letter) Trademark. a brand of tape format for VCR tape, incompatible with other formats.
Compare VHS.
Chiefly British. a grade showing that a student is in the middle or second of three scholastic sections in a class.
Compare alpha (def 7), gamma (def 9).
Origin of beta
< Latin < Greek bêta < Semitic; compare Hebrew bēth beth Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
Cite This Source
Examples from the Web for beta
Contemporary Examples
Historical Examples
British Dictionary definitions for beta


the second letter in the Greek alphabet (Β, β), a consonant, transliterated as b
the second highest grade or mark, as in an examination
  1. involving or relating to electrons: beta emitter
  2. relating to one of two or more allotropes or crystal structures of a solid: beta iron
  3. relating to one of two or more isomeric forms of a chemical compound
Word Origin
from Greek bēta, from Hebrew; see beth


(foll by the genitive case of a specified constellation) a star in a constellation, usually the second brightest: Beta Persei
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Cite This Source
Word Origin and History for beta

second letter of the Greek alphabet, c.1300, from Greek, from Hebrew/Phoenician beth (see alphabet); used to designate the second of many things. Beta radiation is from 1899 (Rutherford). Beta particle is attested from 1904.

Online Etymology Dictionary, © 2010 Douglas Harper
Cite This Source
beta in Medicine

beta be·ta (bā'tə, bē'-)

  1. Symbol β The second letter of the Greek alphabet.

  2. The second item in a series or system of classification.

  3. A beta particle.

  4. A beta ray.

  1. Of or relating to the second position from a designated carbon atom in an organic molecule at which an atom or a radical may be substituted.

  2. Of or relating to an isomeric variation of a chemical compound, such as a stereoisomer.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
Cite This Source

Word of the Day

Nearby words for beta

Word Value for beta

Scrabble Words With Friends