Purify/ˈpjʊrɪfaɪ/ Definition 1 of 3Pro Tip 1/3Practical Uses Purify often refers to making water or air safe and clean for use. Charcoal filters are used to purify drinking water. Pro Tip 2/3Beyond Cleaning Purify implies removing harmful substances, not just dirt or mess. Industrial plants must purify wastewater before releasing it. Pro Tip 3/3Health Safety In health contexts, purify stresses the elimination of germs and bacteria. Hospitals often use UV light to purify the air in rooms.