tooth fairy

tooth fairy idiom
A mythical source of bounty, as in So who will finance this venture—the tooth fairy? This expression refers to the fairy credited with leaving money under a child's pillow in place of a baby tooth that has fallen out, a practice popular with American parents since the first half of the 1900s.

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.

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