proof
n. C / Un. information or evidence that shows something is definitely true. You use this when you want to be certain about a fact.
n. evidence or argument establishing a fact or the truth of a statement. Often used in legal, scientific, or mathematical contexts to denote absolute certainty.
Do you have any proof of your identity?
The scientist presented clear proof that the new medicine works better than the old one.
While the initial data suggested a correlation, the researchers required further longitudinal studies to provide definitive proof of a causal relationship between the two variables.
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.
Uncountable when referring to general evidence; countable when referring to a specific mathematical or logical demonstration.
I have many proofs for thisI have much proof for thisIn general conversation, 'proof' is usually uncountable; 'proofs' is typically reserved for mathematical or printing contexts.