[al-gol, -gawl]


a star of the second magnitude in the constellation Perseus: the first known and most famous eclipsing binary star.

Origin of Algol

1350–1400; Middle English < Arabic, equivalent to al the + ghūl ghoul; as translation of Greek (Ptolemy) gorgónion the head of the Gorgon Medusa, held by Perseus
Also called Demon Star.


[al-gol, -gawl]


a computer language in which information is expressed in algebraic notation and according to the rules of Boolean algebra.

Origin of ALGOL

1955–60; algo(rithmic) l(anguage) Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for algol

Historical Examples of algol

  • Assuming the orbit to be circular, the velocity of Algol was found to be twenty-six miles per second.

    The Story of the Heavens

    Robert Stawell Ball

  • Again, I may refer to the curious phenomena presented by Algol, a bright star in the head of Medusa.

    The Beauties of Nature

    Sir John Lubbock

  • Algenib and Algol form with γ Andromedæ, a right-angled triangle.

    A Field Book of the Stars

    William Tyler Olcott

  • It is thought probable by good authorities that the companion of Algol is not quite dark, but has some inherent light of its own.

    Astronomy of To-day

    Cecil G. Dolmage

  • It will be seen that this star combines the Algol and Beta Lyr types.

British Dictionary definitions for algol




the second brightest star in Perseus, the first known eclipsing binary. Visual magnitude: 2.2–3.5; period: 68.8 hours; spectral type (brighter component): B8V

Word Origin for Algol

C14: from Arabic al ghūl the ghoul




a computer programming language designed for mathematical and scientific purposes; a high-level language

Word Origin for Algol

C20 alg (orithmic) o (riented) l (anguage)
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

Word Origin and History for algol


Beta Persei, variable star in the constellation Perseus, late 14c., literally "the Demon," from Arabic al-ghul "the demon" (see ghoul). It corresponds, in modern representations of the constellation, to the gorgon's head Perseus is holding, but it probably was so called because it visibly varies in brightness every three days, which sets it apart from other bright stars. The computer language (1959) is a contraction of algo(rithmic) l(anguage); see algorithm.

Online Etymology Dictionary, © 2010 Douglas Harper