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See more synonyms for extrapolate on Thesaurus.com
verb (used with object), ex·trap·o·lat·ed, ex·trap·o·lat·ing.
  1. to infer (an unknown) from something that is known; conjecture.
  2. Statistics. to estimate (the value of a variable) outside the tabulated or observed range.
  3. Mathematics. to estimate (a function that is known over a range of values of its independent variable) to values outside the known range.
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verb (used without object), ex·trap·o·lat·ed, ex·trap·o·lat·ing.
  1. to perform extrapolation.
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Origin of extrapolate

First recorded in 1825–35; extra- + (inter)polate
Related formsex·trap·o·la·tion, nounex·trap·o·la·tive, ex·trap·o·la·to·ry [ik-strap-uh-luh-tawr-ee, -tohr-ee] /ɪkˈstræp ə ləˌtɔr i, -ˌtoʊr i/, adjectiveex·trap·o·la·tor, nouno·ver·ex·trap·o·la·tion, noun
Can be confuseddeduction extrapolation induction generalization hypothesis
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words

deduce, hypothesize, guess, theorize, envision, figure, conclude, predict, anticipate, project, assume, foretell, foresee

Examples from the Web for extrapolate

Contemporary Examples

Historical Examples

  • They extrapolate a sequence beautifully—but they can be out-thought.

    Breaking Point

    James E. Gunn

  • Do you extrapolate your mastications, too, and get frightened of the stink you might get?

    Breaking Point

    James E. Gunn

  • "Jamison will extrapolate from there," Cochrane assured him.

    Operation: Outer Space

    William Fitzgerald Jenkins

  • The scientists had worked late, trying to extrapolate their data into some kind of prediction.

    The Flaming Mountain

    Harold Leland Goodwin

  • Jamison began to extrapolate from his observations out the control-room port, adding film-clips for authority.

    Operation: Outer Space

    William Fitzgerald Jenkins

British Dictionary definitions for extrapolate


  1. maths to estimate (a value of a function or measurement) beyond the values already known, by the extension of a curveCompare interpolate (def. 4)
  2. to infer (something not known) by using but not strictly deducing from the known facts
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Derived Formsextrapolation, nounextrapolative or extrapolatory, adjectiveextrapolator, noun

Word Origin

C19: extra- + -polate, as in interpolate
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 extrapolate


1874, a back-formation from extrapolation by analogy of interpolate. Said in early references to be an expression of Sir George Airy (1801-1892), English mathematician and astronomer. Related: Extrapolated; extrapolating.

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Online Etymology Dictionary, © 2010 Douglas Harper

extrapolate in Science


  1. To estimate the value of a quantity that falls outside the range in which its values are known.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.