Discoloration is when something changes to a different color than it's expected to be, usually in an unwanted or unappealing way. When a white shirt develops yellowish stains, that's discoloration. When a bruise turns your skin purple and green, that's discoloration too.

The word describes color changes that happen over time or because of damage, not colors that were there from the start. An old photograph might show brown discoloration around the edges where the paper has aged. A tooth might develop discoloration from drinking too much soda. Leaves on a plant might show white or brown discoloration if the plant is sick or not getting enough water.

Discoloration can happen to almost anything: walls, teeth, fabric, skin, food, or paper. Sometimes it's harmless, like when a peeled apple turns brown after sitting out. Other times it signals a problem, like when discoloration on a wall reveals a water leak.

When something loses its original, healthy color and takes on strange shades instead, you're looking at discoloration.