[ al-fuh ]
See synonyms for alpha on
  1. the first letter of the Greek alphabet (A, α).

  2. the vowel sound represented by this letter.

  1. the first; the beginning.

  2. Alpha, Astronomy. used to designate the brightest star in a constellation.

  3. Chemistry. one of two or more isomeric compounds.

  4. the first in a series of related items: frequently used in chemistry and physics.

  5. Chiefly British. a mark or grade corresponding to an A.: Compare beta (def. 8), gamma (def. 9).

  1. : See also alpha male.

    • (of an animal) having the highest rank in a dominance hierarchy: the alpha female of an elephant pack.

    • being the most dominant, powerful, or assertive person in a particular group.

  2. alphabetical (def. 1): Put the files in alpha order.

  1. Chemistry. pertaining or linked to the carbon atom closest to a particular group in an organic molecule.

Origin of alpha

From Latin, from Greek álpha, from Semitic; cf. aleph

Words Nearby alpha Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use alpha in a sentence

British Dictionary definitions for alpha (1 of 2)


/ (ˈælfə) /

  1. the first letter in the Greek alphabet (Α, α), a vowel transliterated as a

  2. British the highest grade or mark, as in an examination

  1. (modifier)

    • involving or relating to helium-4 nuclei: an alpha particle

    • relating to one of two or more allotropes or crystal structures of a solid: alpha iron

    • relating to one of two or more isomeric forms of a chemical compound, esp one in which a group is attached to the carbon atom to which the principal group is attached

  2. (modifier) denoting the dominant person or animal in a group: the alpha male

Origin of alpha

via Latin from Greek, of Phoenician origin; related to Hebrew āleph, literally: ox

British Dictionary definitions for Alpha (2 of 2)


/ (ˈælfə) /

  1. (foll by the genitive case of a specified constellation) usually the brightest star in a constellation: Alpha Centauri

  2. communications a code word for the letter a

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