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Synonyms

instantaneous

American  
[in-stuhn-tay-nee-uhs] / ˌɪn stənˈteɪ ni əs /

adjective

  1. occurring, done, or completed in an instant.

    an instantaneous response.

    Synonyms:
    abrupt, sudden, immediate
  2. existing at or pertaining to a particular instant.

    the instantaneous position of the rocket.


instantaneous British  
/ ˌɪnstənˈteɪnɪəs /

adjective

  1. occurring with almost no delay; immediate

  2. happening or completed within a moment

    instantaneous death

  3. maths

    1. occurring at or associated with a particular instant

    2. equal to the limit of the average value of a given variable as the time interval over which the variable is considered approaches zero

      instantaneous velocity

"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

Other Word Forms

Etymology

Origin of instantaneous

From the Medieval Latin word instantāneus, dating back to 1645–55. See instant, -an, -eous

Explanation

Something instantaneous is happening right now, without delay. In today's society, the technology we carry in our pockets means people often expect an instantaneous or immediate response to emails and text messages. Instantaneous comes from the Latin instant- meaning "being at hand." When something is instantaneous, it's right at hand when you need it. You can produce an instantaneous reply to someone or see an instantaneous change happen. If something happens very suddenly, you can describe it as instantaneous.

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Vocabulary lists containing instantaneous

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

A camera feeding a screen in front of the pilot relies on instantaneous computer processing to get round the lack of forward vision.

From BBC ● Sep. 24, 2026

Ryan and Myers said they were fascinated with how the American news media covered the kidnapping in instantaneous fashion and in an era long before the internet.

From Los Angeles Times ● Sep. 18, 2026

A newspaper columnist myself a quarter-century later, I am loath to judge strictly the instantaneous reaction of a fellow practitioner.

From The Wall Street Journal ● Sep. 9, 2026

"Such transactions can be sizeable, irregular and instantaneous," the study said.

From Barron's ● Jun. 5, 2026

The response from the students in the crowd was instantaneous, a raucous bout of yells and cries of anger.

From "Anger Is a Gift" by Mark Oshiro

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