The story
From duck + weed. Supposedly so-named for often being consumed by ducks and other waterfowl. Compare Middle English dokemete (“duckweed”, literally “duck-food”).
Etymology from Wiktionary, CC BY-SA 4.0.
duckweed
Today it means: Any of several reduced floating aquatic plants in the subfamily Lemnoideae of the family Araceae. Full definition →