Pure means unmixed or uncontaminated, containing nothing that doesn't belong. Pure water contains only water molecules, with no dirt, chemicals, or other substances mixed in. Pure gold has no other metals blended with it. When scientists need pure samples for experiments, they carefully remove every trace of anything else.

The word also describes things that are complete or absolute. Pure joy means happiness with no worry or sadness mixed in, like the feeling when school lets out for summer vacation. Pure luck means something happened entirely by chance, with no skill involved. A pure white blanket has no other colors in it at all.

People use pure to describe someone genuinely good or innocent, like calling someone pure of heart when they have honest intentions without hidden motives. A pure voice in singing means clear and true, without strain or artificiality.

The opposite of pure is impure or contaminated. Scientists talk about levels of purity: something might be 99% pure, meaning it's mostly one thing with tiny amounts of something else. In chemistry, achieving perfect purity is nearly impossible, but getting close enough matters for experiments to work properly. When something is pure, you know exactly what you're getting, nothing more and nothing less.