A red to purple azo dye used as a biological stain, and in some countries in cosmetics and as a food colouring.
Any of various herbs of the genus Amaranthus.
The characteristic purplish-red colour of the flowers or leaves of these plants.
The seed of these plants, used as a cereal.
A dye (rosaniline hydrochloride, C₂₀H₁₉N₃·HCl) usually a deep red or magenta colour.