noun
or acid magenta
Usage: often capitalized A&F&M
: an acid triphenylmethane dye that is now usually obtained by sulfonation of fuchsine and is used in the form of a salt chiefly in histology as a general cytoplasmic stain and for demonstration of special elements (as mitochondria) and in photographic films as an antihalation dye — see dye table I (under Acid Violet 19 )