Proof is something that shows or tells us that something is true. It can be a paper, a thing, or information that helps us believe a fact.
She showed proof of her identity.
Do you have proof for your answer?
In printing, a proof is a copy made to check for mistakes before the last and final version. It helps people see how the final page or image will look.
The printer made a proof of the book page.
Check the proof before the final print.
Proof can mean a way to check if something is strong or safe. This is done by testing its ability to resist damage or danger.
This machine is fireproof by proof tests.
The helmet passed impact proof tests.
Proof also means 'able to stop or not be harmed by' things like water, fire, or shock. We add it to words to show protection or safety.
This coat is waterproof and warm.
The watch is shockproof and good for sports.
Proof is also used to say how strong an alcoholic drink is. It is a number that tells you how much alcohol is inside the drink.
This whiskey is 90 proof.
The bottle shows 80 proof on the label.
As a verb, proof means to check something carefully to find any mistakes or problems. People often proofread text to make sure it is correct.
Please proof your work carefully.
He proofed the text for mistakes.
Proof can also be a verb meaning to make something safe from damage or harm. For example, to proof a door means to stop water or air going inside.
They proofed the building against fire.
We proofed the box to keep it dry.
