without value, effect, consequence, or significance.
being or amounting to nothing; nil; lacking; nonexistent.
Mathematics. (of a set)
  1. empty.
  2. of measure zero.
being or amounting to zero.


Electronics. a point of minimum signal reception, as on a radio direction finder or other electronic meter.

verb (used with object)

to cancel; make null.


    null and void, without legal force or effect; not valid: This contract is null and void.

Origin of null

1555–65; < Latin nūllus, equivalent to n(e) not + ūllus any Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for null

Contemporary Examples of null

  • Because all of the Rescued Film Project images are scanned to digital, the necessity of a darkroom is null.

    The Daily Beast logo
    These Photographs Would Die Without Him

    Dale Eisinger

    July 31, 2014

  • Journals aren't interested in null results or "yup, we replicated that other study"; they want new studies with new findings.

    The Daily Beast logo
    Searching for Fraud

    Megan McArdle

    October 9, 2012

  • Blacks are saying that the old contract with America is null and void.

    The Daily Beast logo
    America's New Racial Reality

    James Carroll

    September 18, 2009

Historical Examples of null

British Dictionary definitions for null



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

Word Origin for null

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

"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).

Online Etymology Dictionary, © 2010 Douglas Harper

null in Science



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