indigo carmine

indigo carmine

noun

Definition of INDIGO CARMINE

: a soluble blue dye C₁₆H₈N₂Na₂O₈S₂ that is a sodium salt, is used chiefly as a biological stain and food color, and since it is rapidly excreted by the kidneys is used as a dye to mark ureteral structures (as in cystoscopy and catheterization)