a change to the original colour of something that makes it look unpleasant or damaged

Too much fluoride can cause a harmless discoloration of the teeth. 过多的氟化物会导致牙齿变色，虽然这是无害的。

Chips, cracks and discoloration are visible in the concrete. 混凝土中可以看到碎片、裂缝和变色。

Brown discolorations appear on the skin. 皮肤上出现棕色变色。

The North Ormesby area of Middlesbrough has suffered serious discolouration of its drinking water. 米德尔斯堡北奥姆斯比地区发生了饮用水严重变色。