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[rair-uh-fak-shuh n] /ˌrɛər əˈfæk ʃən/
the act or process of rarefying.
the state of being rarefied.
Origin of rarefaction
1595-1605; < Medieval Latin rārēfactiōn- (stem of rārēfactiō), equivalent to Latin rārēfact(us) (past participle of rārēfacere; see rarefy) + -iōn- -ion
Related forms
rarefactional, adjective
[rair-uh-fak-tiv] /ˌrɛər əˈfæk tɪv/ (Show IPA),
Can be confused Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2017.
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Examples from the Web for rarefaction
Historical Examples
  • A sound-wave consists essentially of two parts — a condensation and a rarefaction.

  • With these pumps a higher degree of rarefaction can be obtained.

    Physics Willis Eugene Tower
  • Now here, certainly, there must be evidence of the truth of the rarefaction theory, if any where on the face of the earth.

    The Philosophy of the Weather Thomas Belden Butler
  • This is precisely what is meant by rarefaction and condensation.

  • It would seem to be impossible for any man to believe in the theory of rarefaction, after an examination of these tables.

    The Philosophy of the Weather Thomas Belden Butler
  • The ends of the strip suffer neither condensation nor rarefaction.

    Six Lectures on Light John Tyndall
  • Indicate the parts of the curve that correspond to a condensation and to a rarefaction.

    Physics Willis Eugene Tower
  • Air, therefore, rushes towards those parts where a degree of vacuity or rarefaction has been produced.

    The Reason Why Anonymous
  • We threw over part of our ballast, and mounted up till the cold and the rarefaction of the air became very troublesome.

    Wonderful Balloon Ascents Fulgence Marion
  • Anaximenes — adopted Air as ἀρχή — rise of substances out of it, by condensation and rarefaction.

British Dictionary definitions for rarefaction


the act or process of making less dense or the state of being less dense
Derived Forms
rarefactional, rareficational, rarefactive, adjective
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 rarefaction

c.1600, from Middle French raréfaction or directly from Medieval Latin rarefactionem (nominative rarefactio), noun of action from past participle stem of Latin rarefacere (see rarefy). Used chiefly in reference to gasses.

Online Etymology Dictionary, © 2010 Douglas Harper
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rarefaction in Medicine

rarefaction rar·e·fac·tion (râr'ə-fāk'shən)
A decrease in density and pressure in a medium, such as air, caused by the passage of a sound wave.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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rarefaction in Science
  1. A decrease in density and pressure in a medium, such as air, especially when caused by the passage of a wave, such as a sound wave.

  2. The region in which this occurs.

The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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