instantaneous

American  

[in-stuhn-tey-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.

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instantaneous British  

/ ˌɪnstənˈteɪnɪəs, ɪnˌstæntəˈniːɪtɪ /

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

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Other Word Forms

• instantaneity noun
• instantaneously adverb
• instantaneousness noun

Etymology

Origin of instantaneous

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

Example Sentences

“Access to the classical studies is now instantaneous: literature, science, art, philosophy, mathematics and history.”

From Salon • Mar. 30, 2026

But it also conveys facts, often supported by real-time video, and instantaneous access to underlying truth.

From The Wall Street Journal • Feb. 13, 2026

The almost instantaneous virality from TikTok and the growing amount of collaborations with artists like Metro Boomin and Justin Bieber soon cemented Toliver as a mainstay in the genre.

From Los Angeles Times • Jan. 30, 2026

Despite instantaneous, zero-fee transactions, the explosion of exchange-traded funds, and algorithmic trading, the economic role of the U.S. public markets has been in quiet retreat.

From Barron's • Jan. 2, 2026

Bush could not fail to be impressed by DuBridge’s instantaneous assent and what it indicated about Lawrence’s standing in the scientific community.

From "Big Science" by Michael Hiltzik

Related Words

• rapid
• spontaneous
• transitory