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null

adj. · n. · v.
US //ˈnəɫ// UK //nˈʌl// null
  1. 1 invalid or empty (adj.)
    B2 Upper Intermediate Formal Law

    having no legal power or being equal to nothing.

    having no legal force or validity; alternatively, representing a value of zero or an empty set.

    Example

    The judge declared that the old contract was null and void.

    Example

    The agreement was rendered null and void after it was discovered that one of the signatories had acted without proper legal authority.

    Usage

    Commonly used in the fixed phrase 'null and void'.
  2. 2 an empty value (n.)
    C1 Advanced Technical Computing

    a value that means 'no data' or 'nothing' in a computer program.

    a special marker used in programming to indicate that a data element does not have a value.

    Example

    The program crashed because the database returned a null instead of a name.

    Example

    The developer implemented a check to ensure the function would not execute if the input variable was null.

    Usage

    Often functions as an uncountable noun in technical contexts.
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  1. 3 null hypothesis (n.)
    C1 Advanced Academic Technical Science

    the starting idea in a science test that says there is no change or no effect.

    the hypothesis that there is no significant difference between specified populations, any observed difference being due to sampling or experimental error.

    Example

    The scientists failed to reject the null during their first experiment.

    Example

    Statistical significance was not reached, meaning the researchers could not disprove the null hypothesis regarding the drug's efficacy.

  2. 4 to remove software limits (v.)
    C2 Proficiency Slang Technical Computing

    to break the security on a piece of software so it can be used for free.

    to remove digital rights management or licensing restrictions from software.

    Example

    He found a nulled version of the expensive photo editor online.

    Example

    Using nulled software is a significant security risk as the modified code often contains hidden malware or backdoors.
Origin

Borrowed from Middle French nul, from Latin nūllus.

Idioms1 entry

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