Purity means the state of being unmixed, uncontaminated, or free from anything that would diminish quality or value. When chemists talk about the purity of gold, they mean how much is pure gold versus other metals mixed in. Twenty-four karat gold has the highest purity, while fourteen karat gold contains more other metals. Water purity matters too: pure water contains just hydrogen and oxygen, while contaminated water has dirt, chemicals, or bacteria mixed in.

The word extends beyond physical substances. In music, a pure tone has a single frequency without harmonics or distortion. A pure white surface reflects all colors of light equally, without any tint or shade. Scientists value purity in their experiments because impurities can ruin results.

People also use purity to describe intentions or motives. When someone acts from pure motives, they do something for the right reasons alone, not for praise or reward. A gift given with pure generosity comes from genuine care, not from hoping to get something back.

Related words include purify (to make pure), purification (the process of making something pure), and purist (someone who insists on traditional or unmixed forms of something). A language purist might object to borrowed words from other languages, while a musical purist might prefer original instruments to modern ones.