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1. The condition of being rarefied.
a. A decrease in density and pressure in a medium, such as air, caused by the passage of a sound wave.
b. The region in which this occurs.

rar′e·fac′tive adj.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(ˌrɛərɪˈfækʃən) or


the act or process of making less dense or the state of being less dense
ˌrareˈfactional, ˌrarefiˈcational, ˌrareˈfactive adj
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(ˌrɛər əˈfæk ʃən)

1. the act or process of rarefying.
2. the state of being rarefied.
rar`e•fac′tion•al, adj.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.rarefaction - a decrease in the density of something; "a sound wave causes periodic rarefactions in its medium"
concentration - increase in density
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.


[ˌrɛərɪˈfækʃən] Nrarefacción f
Collins Spanish Dictionary - Complete and Unabridged 8th Edition 2005 © William Collins Sons & Co. Ltd. 1971, 1988 © HarperCollins Publishers 1992, 1993, 1996, 1997, 2000, 2003, 2005


nDünne f; (fig)Exklusivität f
Collins German Dictionary – Complete and Unabridged 7th Edition 2005. © William Collins Sons & Co. Ltd. 1980 © HarperCollins Publishers 1991, 1997, 1999, 2004, 2005, 2007
References in classic literature ?
For some days past, Captain Bonneville had been made sensible of the great elevation of country into which he was gradually ascending by the effect of the dryness and rarefaction of the atmosphere upon his wagons.
5, 2019 (HealthDay News) -- White matter rarefaction, arteriolosclerosis, and dorsolateral frontal cortex (DLFC) neurofibrillary tangles (NFTs) are independently associated with dementia among older men who played football and had chronic traumatic encephalopathy (CTE), according to a study published online Aug.
Ce ralentissement est du, essentiellement, a la rarefaction des projets des operateurs economiques.
We analyzed differences in species richness between the three phytophysiognomies by using both sampled-based and individual-based rarefaction and extrapolation curves with the first Hill number (species richness, q = 0) (Chao et al., 2014; Colwell et al., 2012; Jost, 2007).
In the arising flow with discontinuities, there are typical elements such as a rarefaction wave, a contact discontinuity and a shock wave.
Lastly, rarefaction curves were used to understand the level of sampling in the environment.
[13] Several studies have reported that elevated BP increases the risk of structural and functional rarefaction in different microvascular beds, and may independently predict the subsequent development of clinical cardiovascular disease in the future.
To establish the number of species as a function of sample number, we plotted rarefaction curves, which showed a trend similar to that of the diversity indices (Figure 1).
Presidant la ceremonie d'ouverture du 1er forum exposition agricole international de Jordanie, le prince Hassan ben Talal a indique que la securite alimentaire dans le monde arabe "semble instable Uu l'horizon 2030 our plusieurs facteurs, Uu savoir la forte densite demographique, la rarefaction de l'eau et les changements climatiques".
Given that microvascular dysfunction and rarefaction are unquestionably involved in arterial hypertension pathophysiology and that hypertension can lead to microvascular alterations, a bi-directional causality most likely exists between the two conditions.