Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio.
any of a genus (Myriophyllum, family Haloragaceae) of graceful, feathery dicotyledonous plants (order Haloragales) growing under water: used in aquariums
Used by arrangement with John Wiley & Sons, Inc.
nounThe American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Any of various cosmopolitan aquatic herbs of the genus Myriophyllum, having feathery, finely dissected submersed leaves and entire or toothed emersed leaves.