radish

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

• noun A Eurasian plant (Raphanus sativus) in the mustard family, having a fleshy edible root and white to purple flowers clustered in a terminal raceme.
• noun The pungent root of this plant, often eaten raw.

from The Century Dictionary.

• noun A plant, Raphanus sativus, cultivated for its edible root; also other species of the same genus. (See phrases below.)
• noun A root of this plant.
• noun Same as water-radish.

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

• noun (Bot.) The pungent fleshy root of a well-known cruciferous plant (Raphanus sativus); also, the whole plant.
• noun (Zoöl.) a small two-winged fly (Anthomyia raphani) whose larvæ burrow in radishes. It resembles the onion fly.
• noun (Bot.) an herb (Raphanus caudatus) having a long, slender pod, which is sometimes eaten.
• noun (Bot.) the jointed charlock.

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

• noun A plant of the Brassicaceae family, Raphanus sativus, having an edible root
• noun The pungent root of this plant, usually eaten raw in salads etc

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

• noun a cruciferous plant of the genus Raphanus having a pungent edible root
• noun radish of Japan with a long hard durable root eaten raw or cooked
• noun pungent edible root of any of various cultivated radish plants
• noun Eurasian plant widely cultivated for its edible pungent root usually eaten raw
• noun pungent fleshy edible root