1. a change in color, especially an unwanted darkening or staining of a surface
Usage: British spelling; American spelling is 'discoloration'; commonly used in medical, dental, and material contexts

Examples

• The coffee stain caused permanent discolouration on the white tablecloth.
• Tooth discolouration can result from smoking or drinking red wine.
• The old painting showed significant discolouration from years of exposure to sunlight.
• Rust caused discolouration on the metal gate.
• The dermatologist examined the skin discolouration on the patient's arm.
• Water damage led to discolouration of the ceiling.
• Regular cleaning can help prevent discolouration of bathroom tiles.