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Little pitchers have big ears

Adults must be careful about what they say within the hearing of children. The saying refers to the large handles (ears) sometimes attached to small vessels.

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Idioms and Phrases with little pitchers have big ears

little pitchers have big ears

Young children often overhear something they should not. For example, Don't use any swear words around Brian—little pitchers have big ears. This metaphoric expression, which likens the curved handle of a pitcher to the human ear, was already in John Heywood's proverb collection of 1546.

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.