noun
Usage: often capitalized A&R
: any of various red mordant or acid dyes most of which are derived from anthraquinone: as
a. : turkey red 1a
b. : an orange-yellow crystalline compound C 14 H 7 NaO 7 S used chiefly for dyeing and printing aluminum-mordanted wool scarlet red, as a biological stain, and as an analytical reagent (as for detecting aluminum); sodium 3-alizarin-sulfonate — called also Alizarine Carmine, Alizarine Red S, Alizarine S ; see dye table I (under Mordant Red 3 )