Definition of rarefaction in English:

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Pronunciation: /ˌrɛːrɪˈfakʃ(ə)n/


[mass noun]
1Reduction in the density of something, especially air or a gas: opposed processes such as rarefaction and condensation [count noun]: a series of rarefactions and compactions
More example sentences
  • We hear nothing more of ‘separating out’ or even of rarefaction and condensation.
  • Anaximenes' notion of successive change of matter by rarefaction and condensation was influential in later theories.
  • Sound is a wave of compression and rarefaction in air.
1.1 Medicine The lessening of density of tissue, especially of nervous tissue or bone: the cord has undergone rarefaction
More example sentences
  • Due to the relatively advanced age of the patients included in our study, marked rarefaction of the spongy bone tissue was present, but signs of metabolic bone disease, that is, osteomalacia, were not found in any of the cases.
  • Loss of pain sensation together with possible rarefaction of the bones of the neuropathic foot can have serious consequences.
  • Numerous platelets appeared in the lumen, some of which showed signs of degeneration with swelling and rarefaction.


Early 17th century: from medieval Latin rarefactio(n-), from the verb rarefacere 'grow thin, become rare'.

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Line breaks: rar|efac¦tion

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