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.

---

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

---

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

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.

Example Sentences

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

From Salon • Mar. 30, 2026

"Imagine a humanoid educator named Plato. Access to the classical studies is now instantaneous," she said.

From Barron's • Mar. 25, 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

The unique combination of instantaneous torque, lightweight powertrain and low center of gravity—due to the placement of those heavy batteries—means these vehicles have the potential to be something akin to street-legal Indy cars.

From The Wall Street Journal • Dec. 27, 2025

Besides these they have brought up a number of those little French beasts with instantaneous fuses.

From "All Quiet on the Western Front: A Novel" by Erich Maria Remarque

Related Words

• rapid
• spontaneous
• transitory