old wives' tale
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio.
a silly story or superstitious belief
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 superstitious belief or story belonging to traditional folklore.
old wives' tale - Phrases/Idioms
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
A superstition, as in Toads cause warts? That's an old wives' tale. This expression was already known in ancient Greece, and a version in English was recorded in 1387. Despite invoking bigoted stereotypes of women and old people, it survives.