staining
stain-ing
verb
The act of applying a stain or causing a discoloured mark.
"He spent hours staining the fence panels."
noun
The process of applying a substance to colour or highlight material.
"Microscopic staining helps identify cell structures."
noun
An unwanted mark or discolouration left on a surface.
"The tea caused permanent staining on the tablecloth."
Thesaurus
Synonyms: spotting, maculation