An unfounded rumour or story. Recorded from the mid 19th century, the word comes from French, literally ‘duck’, also ‘hoax’, from Old French caner ‘to quack’. One suggested origin is the expression vendre un canard à moitié ‘half-sell a duck’, with the implication that a half-sale is no sale at all, and therefore the vendor has been fooled. Alternatively, the expression has been attributed to a made-up story about ducks, which was believed by many, and came to exemplify public credulity.
Le Canard Encha[ic]né (‘The Chained Duck’) is the title of a famous French satirical weekly newspaper, founded in 1916.