stain

a soiled or discolored appearance

“the wine left a dark stain”

(microscopy) a dye or other coloring material that is used in microscopy to make structures visible

anything regarded as making something unclean

a symbol of disgrace or infamy

“{'source': 'The Bible, Genesis 4:15', 'text': 'And the Lord set a mark upon Cain'}”

an act that brings discredit to the person who does it

“he made a huge blot on his copybook”

color with a liquid dye or tint

“Stain this table a beautiful walnut color”

“people knew how to stain glass a beautiful blue in the middle ages”

produce or leave stains

“Red wine stains the table cloth”

make dirty or spotty, as by exposure to air; also used metaphorically

“The silver was tarnished by the long exposure to the air”

“Her reputation was sullied after the affair with a married man”

color for microscopic study

“The laboratory worker dyed the specimen”