any of various small stemless aquatic plants of the family Lemnaceae, esp any of the genus Lemna, that have rounded leaves and occur floating on still water in temperate regions
duckweed in American English
(ˈdʌkˌwid)
noun
any of a family (Lemnaceae, order Arales) of monocotyledonous, minute flowering plants that float on ponds and sluggish streams and reproduce by a kind of budding: so called because eaten by ducks