Stain

A stain is a discoloration that can be clearly distinguished from the surface, material, or medium it is found upon.

Accidental staining may make materials appear used, degraded or permanently unclean.

[6] In many cases, stains are affected by heat and may become reactive enough to bond with the underlying material.

Stain removal is frequently a highly desired characteristic in laundry detergents and other types of cleaning agent.

Use of an inappropriate technique could make permanent an otherwise removable stain or cause unwanted discoloration of clothing.

Coffee stains
Stained waistcoat , originally that of a Royal Navy captain of the Victorian era
From a copy of "Decorative Patterns of the Ancient world," by Sir Flinders Petrie. [ 4 ]