verb · 5 senses · updated from the 2026-07-25 local source snapshot
Definitions and examples are grouped by meaning. Pronunciation, history, word forms, translations, descendants, synonyms, antonyms, derived terms, and related words appear whenever the source provides them.
Sound
Pronunciation
Each Play button uses your device's default local English voice, or a natural local fallback. The selected voice name appears after playback. This is synthesized speech, not a source recording.
/ˈɹɛəɹəˌfaɪ/
Southern-England:Recorded audio is listed in the source snapshot.
CMU ARPABET:R EH1 R AH0 F AY0
Digits mark lexical stress: 1 primary, 2 secondary, 0 unstressed.
1
verb
Meaning 1
To make rare, thin, porous, or less dense.
Definition source: English Wiktionary via Wiktextract
Usage: transitive
No example sentence was provided for this meaning.
Meaning relationships
Synonyms: none provided
Antonyms: none provided
2
verb
Meaning 2
To become rare, thin or less dense.
Definition source: English Wiktionary via Wiktextract
Usage: intransitive
No example sentence was provided for this meaning.
Meaning relationships
Synonyms: none provided
Antonyms: none provided
3
verb
Meaning 3
weaken the consistency of (a chemical substance)
Definition source: Princeton WordNet 3.0
No example sentence was provided for this meaning.
Meaning relationships
Synonyms: attenuate
Antonyms: none provided
Broader terms: weaken
4
verb
Meaning 4
make more subtle or refined
Definition source: Princeton WordNet 3.0
No example sentence was provided for this meaning.
Meaning relationships
Synonyms: sublimate, subtilize
Antonyms: none provided
Broader terms: change, alter, modify
5
verb
Meaning 5
lessen the density or solidity of
Definition source: Princeton WordNet 3.0
Examples
The bones are rarefied
Meaning relationships
Synonyms: none provided
Antonyms: none provided
Broader terms: change, alter, modify
History
Etymology
From Middle English rarefien, from Old French rarefier (French raréfier), from Latin rarefacere (“make rare”). By surface analysis, rare + -fy.
Across languages
Translations
46 source translations are retained for this English entry.
Belarusian:
разрэ́джваць
(razrédžvacʹ)
— to make rare etc.
Belarusian:
разрэ́дзіць
(razrédzicʹ)
— to make rare etc.
Bengali:
তরল বা পাতলা করা
(torol ba patola kora)
— to make rare etc.
Bulgarian:
разреждам
(razreždam)
— to make rare etc.
Catalan:
enrarir
— to make rare etc.
Finnish:
harventaa
— to make rare etc.
Finnish:
ohentaa
— to make rare etc.
French:
raréfier
— to make rare etc.
German:
verdünnen
— to make rare etc.
German:
evakuieren
— to make rare etc.
German:
rarefizieren
— to make rare etc.
German:
verfeinern
— to make rare etc.
German:
selektieren
— to make rare etc.
German:
ausdünnen
— to make rare etc.
German:
expandieren
— to make rare etc.
Italian:
rarefare
— to make rare etc.
Latin:
rārēfaciō
— to make rare etc.
Māori:
whakaonge
— to make rare etc.
Polish:
rozcieńczać
— to make rare etc.
Polish:
rozcieńczyć
— to make rare etc.
Polish:
rozrzedzać
— to make rare etc.
Polish:
rozrzedzić
— to make rare etc.
Portuguese:
rarefazer
— to make rare etc.
Romanian:
rarefia
— to make rare etc.
Russian:
разрежа́ть
(razrežátʹ)
— to make rare etc.
Russian:
разреди́ть
(razredítʹ)
— to make rare etc.
Slovene:
razredčiti
— to make rare etc.
Spanish:
rarificar
— to make rare etc.
Spanish:
enrarecer
— to make rare etc.
Spanish:
rarefacer (disused)
— to make rare etc.
Spanish:
rarear
— to make rare etc.
Swedish:
förtunna
— to make rare etc.
Ukrainian:
розрі́джувати
(rozrídžuvaty)
— to make rare etc.
Ukrainian:
розріди́ти
(rozridýty)
— to make rare etc.
Bulgarian:
раздувам
(razduvam)
— to enlarge without adding new matter
Finnish:
harventaa
— to enlarge without adding new matter
Finnish:
ohentaa
— to enlarge without adding new matter
German:
aufblasen
— to enlarge without adding new matter
German:
verlängern
— to enlarge without adding new matter
German:
expandieren
— to enlarge without adding new matter
Polish:
rafinować
— to enlarge without adding new matter
Polish:
zrafinować
— to enlarge without adding new matter
Spanish:
rarear
— to enlarge without adding new matter
Spanish:
rarificarse
— to enlarge without adding new matter
Spanish:
enrarecerse
— to enlarge without adding new matter
Spanish:
rarefacerse (disused)
— to enlarge without adding new matter