Purification is the process of removing unwanted substances or impurities to make something clean, pure, or better. When a water treatment plant performs purification, it filters out dirt, bacteria, and chemicals so the water becomes safe to drink. When chemists purify a sample in a laboratory, they separate the exact substance they need from everything else mixed in with it.

The word applies to many different contexts. Air purifiers remove dust and allergens from the air in your home. Salt purification involves evaporating seawater to leave behind salt crystals. Metal purification separates valuable gold or silver from rock and other minerals.

Purification can also describe spiritual or moral cleansing in religious contexts, like ritual baths or ceremonies meant to make someone spiritually clean. Different cultures throughout history have practiced various forms of purification as part of their religious traditions.

The key idea behind purification is always the same: starting with something mixed or contaminated and ending with something cleaner, purer, or more refined. Whether you're purifying water, separating chemicals, or refining metal, you're removing what doesn't belong to get closer to the substance you actually want.