• synonyms


See more synonyms for null on Thesaurus.com
  1. without value, effect, consequence, or significance.
  2. being or amounting to nothing; nil; lacking; nonexistent.
  3. Mathematics. (of a set)
    1. empty.
    2. of measure zero.
  4. being or amounting to zero.
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  1. Electronics. a point of minimum signal reception, as on a radio direction finder or other electronic meter.
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verb (used with object)
  1. to cancel; make null.
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  1. null and void, without legal force or effect; not valid: This contract is null and void.
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Origin of null

1555–65; < Latin nūllus, equivalent to n(e) not + ūllus any
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words


British Dictionary definitions for null and void


  1. without legal force; invalid; (esp in the phrase null and void)
  2. without value or consequence; useless
  3. lacking distinction; characterlessa null expression
  4. nonexistent; amounting to nothing
  5. maths
    1. quantitatively zero
    2. relating to zero
    3. (of a set) having no members
    4. (of a sequence) having zero as a limit
  6. physics involving measurement in which an instrument has a zero reading, as with a Wheatstone bridge
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Word Origin

C16: from Latin nullus none, from ne not + ullus any
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for null and void



"void of legal force," 1560s, from Middle French nul, from Latin nullus "not any, none," from ne- "not, no" (see un-) + illus "any," diminutive of unus "one" (see one).

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Online Etymology Dictionary, © 2010 Douglas Harper

null and void in Science


  1. Of or relating to a set having no members or to zero magnitude.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Idioms and Phrases with null and void

null and void

Canceled, invalid, as in The lease is now null and void. This phrase is actually redundant, since null means “void,” that is, “ineffective.” It was first recorded in 1669.

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