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 the pleasure of the OpenAI generated is instantaneous and intoxicating. —Fran Hoepfner, Vulture, 27 Mar. 2025

With hair only growing about a half-inch a month on average, results are sadly not instantaneous. —Lisa Desantis, Glamour, 26 Mar. 2025

First of all, an EV can't ever turn the electronic nannies off entirely, because electric motors will rev to the moon with instantaneous torque the very instant their tires lose traction. —Michael Teo Van Runkle, Ars Technica, 25 Mar. 2025

The instantaneous availability of such information will negate the need for many meetings, calls and messages that take place today. —Mark Settle, Forbes, 20 Mar. 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