Noun

Singular proof

Plural proofs

proof (plural proofs)

1. Any effort, process, or operation designed to establish or discover a fact or truth; an act of testing; a test; a trial.
   • (A date for this quote is being sought): Edmund Spenser,

     For whatsoever mother wit or art Could work, he put in proof.

   • (A date for this quote is being sought): Ford,

     You shall have many proofs to show your skill.

   • (A date for this quote is being sought): Ure,

     Formerly, a very rude mode of ascertaining the strength of spirits was practiced, called the proof.

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.
   • (A date for this quote is being sought): William Shakespeare,

     I'll have some proof.

   • (A date for this quote is being sought): Ralph Waldo Emerson,

     It is no proof of a man's understanding to be able to confirm whatever he pleases.

   • 1990 October 28, Paul Simon, “Proof”, The Rhythm of the Saints, Warner Bros.

     Faith, faith is an island in the setting sun / But proof, proof is the bottom line for everyone

3. The quality or state of having been proved or tried; firmness or hardness which resists impression, or doesn't yield to force; impenetrability of physical bodies.
4. Firmness of mind; stability not to be shaken.
5. (printing) A proof sheet; a trial impression, as from type, taken for correction or examination.
6. (mathematics): A process for testing the accuracy of an operation performed. Compare prove, transitive verb, 5.
7. (obsolete): Armour of excellent or tried quality, and deemed impenetrable; properly, armour of proof.
8. (US) A measure of the alcohol content of liquor. Originally, in Britain, 100 proof was defined as 57.1% by volume (not used anymore). In the US, 100 proof means that the alcohol content is 50% of the total volume of the liquid, and thus, absolute alcohol would be 200 proof.

Synonyms

• testimony
• evidence
• reason
• argument
• trial
• demonstration

Derived terms

• artist's proof
• burden of proof
• proof reader
• proof of concept

Related terms

• prove
• probe

Proof may refer to:

• Formal proof
• Mathematical proof
• Argument
• Proof theory, a branch of mathematical logic that represents proofs as formal mathematical objects
• Justification, in epistemology, a reason for or explanation of a proposition or belief
• Provability logic
• Evidence (law), tested evidence or a legal proof
• Proofing (baking technique), the process by which a yeast-leavened dough rises, also called "proving"
• Recursively enumerable set also know as a provable set

Various kinds of testing, checking, or measuring:

• Proofreading
• Artist's proof, a single print taken during the printmaking process
• Proof coinage, a coin made as an example of a particular strike
• Proof test, for a firearm
• Homeopathic proving, a homeopathic procedure
• Galley proof, a preliminary version of a publication
• Alcoholic proof, a measure of an alcoholic drink's strength
• Proof procedure
• Proof complexity

In entertainment:

• Proof (1991 film), an Australian film by Jocelyn Moorhouse
• Proof (play), a play by David Auburn
• Proof (2005 film), a film directed by John Madden, based on the play
• "Proof", a B-side by the band Coldplay, off their single "Speed of Sound"
• "Proof", a song by Paul Simon from his 1990 album The Rhythm of the Saints
• "Proof", a song by Happy Rhodes from her 1998 album Many Worlds Are Born Tonight
• "Proof", a 2004 song by J-pop group angela
• "Proof", a 2007 song by Japanese artist Mell
• Proof (rapper) (1973–2006), American rapper and member of D12
• Proof (comics), a comic series from Image Comics