amaranth

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of various annual plants of the genus Amaranthus having dense green or reddish clusters of tiny flowers and including weeds, ornamentals, and species cultivated for their edible leaves and seeds.
• noun The small edible seeds of several of these species.
• noun An imaginary flower that never fades.
• noun A deep reddish purple to dark or grayish, purplish red.
• noun A dark red to purple azo dye.

from The Century Dictionary.

• noun An imaginary flower supposed never to fade: used chiefly in poetry.
• noun A plant of the genus Amarantus (which see). The globe-amaranth, Gomphrena globosa, of the same natural order.
• noun A name given to mixtures of coloring matters of which the chief constituent is magenta (which see).
• noun Same as purple heart.
• noun An acid dyestuff, of the monoazo type, which dyes wool and silk a pure bluish red that is moderately fast to light and milling. It is known by various other names, as azo acid-rubine, Bordeaux S, and fast red.

from the GNU version of the Collaborative International Dictionary of English.

• noun Poetic An imaginary flower supposed never to fade.
• noun (Bot.) A genus of ornamental annual plants (Amaranthus) of many species, with green, purplish, or crimson flowers.
• noun A color inclining to purple.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Any of various herbs, of the genus Amaranthus.
• noun Their flowers' characteristic purplish red color; a red to purple azo dye used as a food colouring and in cosmetics.
• noun The seed of these plants, used as a cereal.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun seed of amaranth plants used as a native cereal in Central and South America
• noun any of various plants of the genus Amaranthus having dense plumes of green or red flowers; often cultivated for food