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

Both have the same manually wound movement (the in-house CH 29-535 PS Q) with apertures for day/night, day, month, leap year, and moon phases, plus an instantaneous 30-minute counter and a small seconds subdial. — Rachel Cormack, Robb Report, 7 Nov. 2026

Commissioner Rob Manfred has portrayed the instantaneous lockout as a means of moving the talks along. — Evan Drellich, New York Times, 29 Oct. 2026

Cameras can’t see through dense fog or measure instantaneous velocity like radar can. — Andrew J. Hawkins, The Verge, 27 Oct. 2026

This configuration feeds real-time grip, yaw and velocity data into a central computer, executing independent, instantaneous torque vectoring across the rear wheels. — New Atlas, 15 Oct. 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