Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio.
a tick trefoil (Desmodium gyrans) of tropical Asia: so called because the two lateral leaflets of each leaf move like a railroad semaphore signal
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.
A tropical Asian plant (Desmodium motorium) having trifoliolate compound leaves, whose lateral leaflets are very small and move by jerks under the influence of sunshine.