urban legend

American  

noun

1. a modern story of obscure origin and with little or no supporting evidence that spreads spontaneously in varying forms and often has elements of humor, moralizing, or horror.

   Are there alligators living in the New York City sewer system, or is that just an urban legend?

---

Etymology

Origin of urban legend

First recorded in 1970–75

Example Sentences

After decades of urban legends about poisoned candy, it may be hard to trust in the ritual’s safety.

From The Wall Street Journal

The best of Amélie’s schemes — one that appropriates an old urban legend — is the one that isn’t explained until the end.

From Salon

Most of the stories were tall tales and urban legends told to entertain or to score some popularity.

From Salon

Now the "furry" urban legend is adding more fuel to the fire.

From Salon

Sure, the so-called theory of dad strength — gains in physical strength and stamina that some new dads seemingly experience upon entering fatherhood — might be more of a playful urban legend than scientifically proven fact.

From Los Angeles Times