rarefy

[ rair-uh-fahy ]
/ ˈrɛər əˌfaɪ /

verb (used with object), rar·e·fied, rar·e·fy·ing.

to make rare or rarer; make less dense: to rarefy a gas.
to make more refined, spiritual, or exalted.

verb (used without object), rar·e·fied, rar·e·fy·ing.

to become rare or less dense; become thinned: Moisture rarefies when heated.

Origin of rarefy

1350–1400; Middle English rarefien < Middle French rarefier < Latin rārēfacere, equivalent to rārē-, combining form of rārus rare1 (for expected rāri-; orig. of -ē- unclear) + facere to make; see -fy

OTHER WORDS FROM rarefy

rar·e·fi·a·ble, adjectiverar·e·fi·er, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

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British Dictionary definitions for rarefy

rarefy
/ (ˈrɛərɪˌfaɪ) /

verb -fies, -fying or -fied

to make or become rarer or less dense; thin out

Derived forms of rarefy

rarefiable, adjectiverarefier, noun

Word Origin for rarefy

C14: from Old French raréfier, from Latin rārēfacere, from rārus rare 1 + facere to make
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