acid dye

dye (di) any colored substance containing auxochromes and thus capable of coloring substances to which it is applied; used for staining and coloring, as a test reagent, and as a therapeutic agent.

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acid dye , acidic dye one which is acidic in reaction and usually unites with positively charged ions of the material acted upon.

amphoteric dye  one containing both reactive basic and reactive acidic groups, and staining both acidic and basic elements.

anionic dye  acid d.

basic dye  one which is basic in reaction and unites with negatively charged ions of the material acted upon.

cationic dye  basic d.

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acid dye

n.

Any of a class of dyes that contain acidic groups, usually in the form of sodium or potassium salts, and are used in staining cytoplasm and various acidophilic structures of cells or tissues. Also called acid stain.