discolored

Discolored is an adjective used to describe something whose color has changed from its original or expected appearance. The change can be partial or complete and may affect objects, materials, or living tissue. Discoloration results from a variety of factors, including chemical reactions, environmental exposure, wear, staining, or biological growth.

Common causes include chemical reactions such as oxidation or photo degradation, exposure to light, heat, moisture, or pollutants, and the deposition of dyes, minerals, or mold. Biological processes—such as fungal growth on food or pigment changes in skin or teeth—also produce discoloration. Aging and processing can contribute as well; for example, paper and textiles may yellow over time due to the breakdown of lignin or dyes.

Contexts in which discoloration is observed vary widely. Metals may tarnish or corrode, producing blues, browns, or greens. Paper and textiles can yellow or brown with age. Foods may develop off colors due to spoilage or oxidation. Teeth can exhibit extrinsic stains from coffee, tea, or tobacco or intrinsic discoloration from medications or trauma. Skin may show hyperpigmentation, hypopigmentation, bruising, or other vascular changes.

In practice, discoloration is generally noted as a deviation from a standard color and may or may not indicate damage, depending on the material and context. Prevention and remediation depend on cause and material, ranging from storage and protective measures to cleaning, bleaching, or restoration in more advanced cases.