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Definition of "dead letter" [dead letter]

  • An unclaimed or undelivered letter that after a period of time is destroyed or returned to the sender by the postal service. (noun)
  • A law, directive, or factor still formally in effect but no longer valid or enforced. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Use "dead letter" in a sentence
  • "Sheriff Peppin, with his cohorts, had retired from active service after the bloody nineteenth of July, and law was a dead letter in the county."
  • "The legislature may enact laws for a dozen years in succession -- but if they are not palatable to the people, they will remain a dead letter in the statute-book."