azo dye(n = noun.substance) - any dye containing one or more azo groups;
is a kind of dye, dyestuff
has particulars: congo red, methyl orange

acid dye, aniline dye, azo, azo group, azo radical, basic dye, cyanine dye, direct dye, double dye, dye, fast dye, fluorescent dye, hair dye, lac dye, metallized dye, radiopaque dye, substantive dye, vat dye