To oxygenate something means to add oxygen to it or supply it with oxygen. Your body constantly oxygenates your blood: every time you breathe in, your lungs absorb oxygen from the air and transfer it into your bloodstream, which then carries that oxygen to every cell in your body. Without this continuous process, your cells couldn't produce the energy they need to function.

Fish tanks need oxygenation too. The bubbler in an aquarium doesn't just look cool: it oxygenates the water so fish can breathe. Moving water, like a stream tumbling over rocks, naturally oxygenates itself as it splashes and mixes with air. Pond owners sometimes use fountains or waterfalls to keep their ponds oxygenated for fish and plants.

Gardeners talk about oxygenating soil by loosening it up so air can reach plant roots. Doctors sometimes need to oxygenate a patient's blood if they're having trouble breathing, using oxygen masks or other medical equipment. The related word oxygenated describes something that contains plenty of oxygen, like the bright red, oxygenated blood leaving your lungs versus the darker blood returning to the lungs to pick up more oxygen.