instantaneous

adjective

in·​stan·​ta·​neous ˌin(t)-stən-ˈtā-nē-əs 

-nyəs

1

: done, occurring, or acting without any perceptible duration of time

death was instantaneous

2

: done without any delay being purposely introduced

took instantaneous corrective action

3

: occurring or present at a particular instant

instantaneous velocity

instantaneity

ˌin-ˌstan-tə-ˈnē-ə-tē 

ˌin(t)-stən-tə-ˈnē-

noun

instantaneously

ˌin(t)-stən-ˈtā-nē-əs-lē 

-nyəs-lē

adverb

instantaneousness noun

Synonyms

• immediate
• instant

Examples of instantaneous in a Sentence

We got an almost instantaneous response from the company.

the thunder following the flash of lightning was nearly instantaneous

Recent Examples on the Web

As Figma went public this week to much fanfare—and an almost instantaneous 250% stock pop—quite a few folks from Silicon Valley made money. —Allie Garfinkle, Fortune, 2 Aug. 2025

Now, gathering the necessary trade information, using that data to vet a stock and making the trade is virtually instantaneous. —Harry Temkin, Forbes.com, 1 Aug. 2025

Unlike conventional cross-border bank transfers that can take several days and incur steep processing fees, stablecoin transactions are nearly instantaneous and substantially cheaper, experts pointed out. —Anniek Bao, CNBC, 1 Aug. 2025

Infected saliva from the tick can spread Lyme disease to humans during this process, but infection isn’t instantaneous. —Jack Knudson, Discover Magazine, 4 June 2025

Word History

Etymology

borrowed from Medieval Latin instantāneus, from instant-, instans "moment, point of time," + Latin -āneus, suffix forming adjectives from temporal adverbs — more at instant entry 1

Note: Regarding the suffix -āneus see the etymology and note at spontaneous.

First Known Use

1651, in the meaning defined at sense 1

Rhymes for instantaneous

• aeneas

Kids Definition

instantaneous

adjective

in·​stan·​ta·​neous ˌin(t)-stən-ˈtā-nē-əs 

-nyəs

1

: happening in an instant

2

: done without delay

instantaneously adverb

instantaneousness noun