Definition of "water chestnut" []

• A floating aquatic plant (Trapa natans) native to Eurasia and Africa, bearing four-pronged nutlike fruit and grown as a pond or aquarium ornamental. Also called caltrop, water caltrop. (noun)
• A tropical Asian aquatic sedge (Eleocharis dulcis) having an edible corm and cylindrical leaves. (noun)
• The succulent corm of this plant, used in Asian cooking. Also called Chinese water chestnut. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.