absorption indicator(n = noun.substance) - an indicator used in reactions that involve precipitation;
is a kind of indicator
has particulars: fluorescein, fluoresceine, fluorescent dye, resorcinolphthalein
absorption, absorption band, absorption coefficient, absorption factor, absorption spectrum, absorption unit, acid-base indicator, coefficient of absorption, flight indicator, fuel indicator, indicator, indicator lamp, leading indicator, oxidation-reduction indicator, speed indicator, torsion indicator, turn indicator