1. Also called Tyr'ian dye'. a highly prized crimson or purple dye of classical antiquity, originally obtained at great expense from a certain shellfish: later shown to be an indigo derivative and synthetically produced, and now replaced by other synthetic dyes.
2. a vivid, purplish red.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.