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[proh-lawg, -log] /ˈproʊ lɔg, -lɒg/
a preliminary discourse; a preface or introductory part of a discourse, poem, or novel.
an introductory speech, often in verse, calling attention to the theme of a play.
the actor or actress who delivers this.
an introductory scene, preceding the first act of a play, opera, etc.
any introductory proceeding, event, etc.:
Appetizing delicacies were the prologue to a long dinner.
verb (used with object), prologued, prologuing.
to introduce with or as if with a prologue.
Also, prolog.
1250-1300; Middle English prologe, prologue (< Old French prologue) < Latin prōlogus < Greek prólogos. See pro-2, -logue
Related forms
prologuist, prologist, noun
prologuelike, prologlike, adjective
unprologued, adjective
5. preamble; beginning, opening; prelude. Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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British Dictionary definitions for prolog


a computer programming language based on mathematical logic
Word Origin
C20: from pro(gramming in) log(ic)


  1. the prefatory lines introducing a play or speech
  2. the actor speaking these lines
a preliminary act or event
(in early opera)
  1. an introductory scene in which a narrator summarizes the main action of the work
  2. a brief independent play preceding the opera, esp one in honour of a patron
verb -logues, -loguing, -logued (US) -logs, -loging, -loged
(transitive) to introduce or preface with or as if with a prologue
Word Origin
C13: from Latin prologus, from Greek prologos, from pro-² + logos discourse
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
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Word Origin and History for prolog



early 14c., from Old French prologue (12c.) and directly from Latin prologus, from Greek prologos "preface to a play, speaker of a prologue," literally "a speech beforehand," from pro- "before" (see pro-) + logos "discourse, speech," from legein "to speak" (see lecture (n.)).

Online Etymology Dictionary, © 2010 Douglas Harper
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prolog in Technology
Programming in Logic or (French) Programmation en Logique. The first of the huge family of logic programming languages.
Prolog was invented by Alain Colmerauer and Phillipe Roussel at the University of Aix-Marseille in 1971. It was first implemented 1972 in ALGOL-W. It was designed originally for natural-language processing but has become one of the most widely used languages for artificial intelligence.
It is based on LUSH (or SLD) resolution theorem proving and unification. The first versions had no user-defined functions and no control structure other than the built-in depth-first search with backtracking. Early collaboration between Marseille and Robert Kowalski at University of Edinburgh continued until about 1975.
Early implementations included C-Prolog, ESLPDPRO, Frolic, LM-Prolog, Open Prolog, SB-Prolog, UPMAIL Tricia Prolog. In 1998, the most common Prologs in use are Quintus Prolog, SICSTUS Prolog, LPA Prolog, SWI Prolog, AMZI Prolog, SNI Prolog.
ISO draft standard at Darmstadt, Germany ( or UGA, USA (
See also negation by failure, Kamin's interpreters, Paradigms of AI Programming, Aditi.
A Prolog interpreter in Scheme. (
A Prolog package ( from the University of Calgary features delayed goals and interval arithmetic. It requires Scheme with continuations.
["Programming in Prolog", W.F. Clocksin & C.S. Mellish, Springer, 1985].
The Free On-line Dictionary of Computing, © Denis Howe 2010
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Encyclopedia Article for prolog


prefatory and supplementary pieces to a literary work, especially a verse drama. The ancient Greek prologos was of wider significance than the modern prologue, effectually taking the place of an explanatory first act. A character, often a deity, appeared on the empty stage to explain events prior to the action of the drama, which consisted mainly of a catastrophe. On the Latin stage, the prologue was generally more elaborately written, as in the case of Plautus' Rudens, which contains some of his finest poetry.

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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