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 of instantaneous

• 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

Because the data is instantaneous, even a single day off can set off 20 phone alerts. —Aiko Bethea, Big Think, 22 Apr. 2026

One is instantaneous, the brain just flips into unrecognizable thoughts, and the other is a deterioration over time. —Tony Maglio, HollywoodReporter, 21 Apr. 2026

By all accounts, virality is violent for its subjects, and building a sustainable career from sudden celebrity is a formidable task; any sensible person would be wise to distrust such an instantaneous anointing. —Amanda Petrusich, New Yorker, 13 Apr. 2026

Not only has Martone’s impact been instantaneous, but there’s also every reason to be wildly excited about the 19-year-old’s future. —Kevin Kurz, New York Times, 10 Apr. 2026

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