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
• split-second
• straightaway

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

But its adoption isn’t instantaneous, giving us time to adapt and find ways to balance innovation with workforce stability. —Kurt Knutsson, Cyberguy Report, FOXNews.com, 12 Apr. 2025

Indeed, swiping through pages and navigating through the interface is instantaneous. —PC Magazine, 9 Apr. 2025

Autonomous Vehicles: Vehicles with edge capabilities make instantaneous decisions to improve safety and navigation. —Madhu Gaganam, Forbes, 13 Mar. 2025

The band’s eponymous debut was recorded mere weeks after the four members of the band played in a room together for the first time, and their musical chemistry was instantaneous. —Al Shipley, SPIN, 19 Feb. 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