stain vs crystal violet

stain and crystal violet both are nouns.

Word	Noun	Adjective	Verb	Adverb
stain	Yes	No	Yes	No
crystal violet	Yes	No	No	No

As nouns, crystal violet is a hyponym of stain; that is, crystal violet is a word with a more specific, narrower meaning than stain:

stain: (microscopy) a dye or other coloring material that is used in microscopy to make structures visible
crystal violet: a green crystal (violet in water) used as a dye or stain or bactericide or fungicide or anthelmintic or burn treatment

Other hyponyms of stain include gentian violet, methylene blue, methylthionine chloride, counterstain.

stain (noun)	crystal violet (noun)
an act that brings discredit to the person who does it	a green crystal (violet in water) used as a dye or stain or bactericide or fungicide or anthelmintic or burn treatment
a soiled or discolored appearance
a symbol of disgrace or infamy
anything regarded as making something unclean
(microscopy) a dye or other coloring material that is used in microscopy to make structures visible

stain (verb)	crystal violet (verb)
produce or leave stains
color with a liquid dye or tint
color for microscopic study
make dirty or spotty, as by exposure to air; also used metaphorically