proof
UK[pruːf]US[pruːf]
n
Evidence or argument establishing a fact or the truth of a statement.
n
A trial impression of a printed page, used to make corrections before final printing.
n
The strength of distilled alcoholic liquor, relative to proof spirit taken as a standard of 100.
adj
Able to withstand something damaging; resistant.
v
Make (something) proof, especially waterproof.
Etymology
The word 'proof' entered English in the late 13th century from Anglo-Norman, carrying the core sense of "evidence" or "test". It traces back to the Latin verb 'probare' (to test, prove), itself derived from the adjective 'probus' meaning "good, worthy, honest". This lineage connects the concept of proof to the fundamental idea of demonstrating worthiness or truth through testing. The semantic journey evolved from the act of testing ('probare') to the result that establishes truth ('proof'), and later extended to mean resistance (as in 'waterproof'), implying something that has been tested and found good against a force. The specialized printing and alcohol senses are later metaphorical applications of this core concept of a standard or test.
Analysis
The modern English word 'proof' is a simplex form derived from the Anglo-Norman and Old French 'proeve', 'preuve', meaning "evidence, test". Its ultimate origin is the Latin verb 'probare', meaning "to test, prove, approve".
Examples
The scientist presented concrete proof of her hypothesis.
The author carefully reviewed the page proofs before the book went to press.
This fabric is treated to be water-proof and stain-resistant.