proof
/pɹuf/noun, adjective, verb
proof is spelled P-R-O-O-F: 5 letters and one syllable. It appears 50 times per million words in written English, the 2,041st most frequent word form (wordfreq, 2021 data). People search “proof vs prove” about 720 times a month (Google, United States). As a noun, proof means “An effort, process, or operation designed to establish or discover a fact or truth; an act of testing; a test; a trial” (English Wiktionary, September 2026). The plural of proof is proofs.
How many letters and syllables are in proof?
| Letters | 5: P-R-O-O-F |
|---|---|
| Syllables | 1 (from its American pronunciation) |
| In writing | 50 times per million words; the 2,041st most frequent word form |
| Wrong spellings searched | none measured in search |
| Pairs people search | |
| Rhymes with |
Sources: letters and syllables from the English Wiktionary's hyphenation or pronunciation and the CMU Pronouncing Dictionary; written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media); Bing searches in the United States: the average month from September 2025 to August 2026 (Microsoft Advertising keyword data through DataForSEO, read September 30, 2026); rhymes and same-letter words are computed by PlainSpell from its own word list.
How common is proof?
Proof appears 50 times per million words in written English, the 2,041st most frequent word form in the list.
Source: written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).
How do you pronounce proof?
- UK /pɹuːf/
- US /pɹuf/
- Australia /pɹʉːf/
Proof has one syllable (counted from its American pronunciation in the CMU Pronouncing Dictionary).
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Recordings: En-us-proof.ogg, Wikimedia Commons (author and licence on each file's page).
Words people confuse with proof
Word pairs people search, with the monthly searches for “a vs b” (G: Google, B: Bing, United States).
Also written: prove.
Sources: Google and Bing searches (September 2025 to August 2026, through DataForSEO); English Wiktionary (homophones, alternative spellings).
What rhymes with proof?
6 words on PlainSpell end in the same sounds as proof from its last stressed vowel (/uf/):
Computed by PlainSpell from the pronunciations in the English Wiktionary (dump of September 2, 2026): a rhyme shares every sound from the last stressed vowel to the end; ordered by written frequency (wordfreq 3.1).
Forms of proof
- proofs plural, present, singular, he/she/it
- more proof comparative
- most proof superlative
- proofing participle, present
- proofed participle, past
- more -proof comparative
- most -proof superlative
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).
What does proof mean?
The meanings the English Wiktionary records, quoted as written there (source below).
noun
- 1
An effort, process, or operation designed to establish or discover a fact or truth; an act of testing; a test; a trial.
I need proof of your unconditional love. Lend me some dough.
- 2
The degree of evidence which convinces the mind of any truth or fact, and produces belief; a test by facts or arguments which induce, or tend to induce, certainty of the judgment; conclusive evidence; demonstration.
- 3
The quality or state of having been proved or tried; firmness or hardness which resists impression, or does not yield to force; impenetrability of physical bodies.
- 4
obsoleteExperience of something.
- 5
obsoleteFirmness of mind; stability not to be shaken.
- 6
A proof sheet; a trial impression, as from type, taken for correction or examination.
- 7
A limited-run high-quality strike of a particular coin, originally as a test run, although nowadays mostly for collectors' sets.
- 8
A sequence of statements consisting of axioms, assumptions, statements already demonstrated in another proof, and statements that logically follow from previous statements in the sequence, and which concludes with a statement that is the object of the proof.
adjective
- 1
Used in proving or testing.
a proof load; a proof charge
- 2
Firm or successful in resisting.
proof against harm
- 3
Being of a certain standard as to alcohol content.
60% proof liquor
verb
- 1
colloquialTo proofread.
- 2
To make resistant, especially to water.
- 3
To test-fire with a load considerably more powerful than the firearm in question's rated maximum chamber pressure, in order to establish the firearm's ability to withstand pressures well in excess of those expected in service without bursting.
- 4
To allow (yeast-containing dough) to rise, especially after it has been shaped
dough proofing
- 5
To test the activeness of (yeast).
yeast proofing
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).
Proof in Spanish, French, German and Portuguese
| Language | Words |
|---|---|
| French | preuve , épreuve , résistant à, à l'épreuve de, imperméable à, hermétique à |
| German | Beweis , Korrekturabzug, Druckfahne , -fest , polierte Platte , aufgehen lassen |
| Portuguese | prova , anti-, à prova de , provado |
| Spanish | prueba, comprobación, constatación, ejecutoria , a prueba de |
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Translations are Wiktionary's, by sense; a linked word has its own PlainSpell page.
Where does proof come from?
From Middle English proof, from Old French prove, from Late Latin proba (“a proof”), from Latin probō (“to prove”); see prove; compare also the doublet probe.
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).