Oh
no, a pee stain.
A stain is a permanent
discoloration that can be clearly distinguished from the
surface, material, or medium it is found upon. Stains
are caused by the chemical or physical interaction of
two dissimilar materials. Stains are used intentionally
in a variety of fields, including in research (biochemical
staining), technology (metal staining), and art (wood
staining, stained glass.)... |
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