Meanings
present singular third person rarefies · participle present rarefying · participle past rarefied · past rarefied · alternative proscribed sometimes rarify
- transitiveTo make rare, thin, porous, or less dense.
By means of this gauge, Mr. Smeaton judged that his machine was incomparably better than any former one, as it seemed to rarefy the air in the receiver 1000, or even 2000 times, while the best of these only rarefied it about 140[…]
1815, A Philosophical and Mathematical Dictionary: Containing an Explanation of the Terms, and an Account ... by Charles Hutton ... vol. 1[-2], page 56 - intransitiveTo become rare, thin or less dense.
Given the high quantity of water molecules in the human body it is worthy of note at this point that moisture rarefies when heated.[…]
2019 November 29, Peta Morton, Ancient Teachings for Modern Times: The Way To a Rich and Deeply Satisfying Life, John Hunt Publishing, →ISBN2 more examples
For if The^([sic]) water rarefies and then Condenses, all that great mass of water of the Lake of the Ilinois rises in its vast basin when it rarefies, and falls when it condenses. And, as water always rises as much as it falls, it would[…]
1916, Wisconsin Geological and Natural History Survey, Bulletin, page 293As water rarefies, it evaporates, forming visible steam, and this may be a step toward the final category of reality, fire. Anyone who has held a hand over a boiling kettle may feel the truth of this.[…]
2009, John C. Malone, Psychology: Pythagoras to Present, MIT Press, →ISBN, page 28
Synonyms & antonyms
Synonym sets from Open English WordNet, CC BY 4.0.
Origin
- Latinrarefacere“make rare”
- Old Frenchrarefier
- Middle Englishrarefien
- Englishrarefy
From Middle English rarefien, from Old French rarefier (French raréfier), from Latin rarefacere (“make rare”). By surface analysis, rare + -fy.
More words from Middle English, Old French, Latin
Full word history & related roots →Translations
Bengali তরল বা পাতলা করা
- তরল বা পাতলা করা (torol ba patola kora)to make rare etc.
Bulgarian разреждам, раздувам
- разреждам (razreždam)to make rare etc.
- раздувам (razduvam)to enlarge without adding new matter
Catalan enrarir
- enrarirto make rare etc.
Finnish harventaa, ohentaa
- harventaato make rare etc.
- ohentaato make rare etc.
- harventaato enlarge without adding new matter
- ohentaato enlarge without adding new matter
French raréfier
- raréfierto make rare etc.
German verdünnen, evakuieren
- verdünnento make rare etc.
- evakuierento make rare etc.
- rarefizierento make rare etc.
- verfeinernto make rare etc.
- selektierento make rare etc.
- ausdünnento make rare etc.
- expandierento make rare etc.
- aufblasento enlarge without adding new matter
- verlängernto enlarge without adding new matter
- expandierento enlarge without adding new matter
Italian rarefare
- rarefareto make rare etc.
Latin rārēfaciō
- rārēfaciōto make rare etc.
Māori whakaonge
- whakaongeto make rare etc.
Polish rozcieńczać, rozcieńczyć
- rozcieńczaćto make rare etc.
- rozcieńczyćto make rare etc.
- rozrzedzaćto make rare etc.
- rozrzedzićto make rare etc.
- rafinowaćto enlarge without adding new matter
- zrafinowaćto enlarge without adding new matter
Portuguese rarefazer
- rarefazerto make rare etc.
Romanian rarefia
- rarefiato make rare etc.
Russian разрежа́ть, разреди́ть
- разрежа́ть (razrežátʹ)to make rare etc.
- разреди́ть (razredítʹ)to make rare etc.
Spanish rarificar, enrarecer
- rarificarto make rare etc.
- enrarecerto make rare etc.
- rarefacerto make rare etc.
- rarearto make rare etc.
- rarearto enlarge without adding new matter
- rarificarseto enlarge without adding new matter
- enrarecerto enlarge without adding new matter
- rarefacerseto enlarge without adding new matter
Swedish förtunna
- förtunnato make rare etc.
Ukrainian розрі́джувати, розріди́ти
- розрі́джувати (rozrídžuvaty)to make rare etc.
- розріди́ти (rozridýty)to make rare etc.
Rhymes & wordplay
Anagrams
Cite this entry
rarefy. (n.d.). In WatkinsX Dictionary. Retrieved November 3, 2026, from https://dictionary.watkinsx.com/word/rarefy
“rarefy.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/rarefy. Accessed November 3, 2026.
WatkinsX Dictionary, s.v. “rarefy,” accessed November 3, 2026, https://dictionary.watkinsx.com/word/rarefy.
Source: rarefy on Wiktionary, CC BY-SA 4.0.