seismic

adjective

seis·​mic ˈsīz-mik 

ˈsīs-

1

: of, subject to, or caused by an earthquake

also : of or relating to an earth vibration caused by something else (such as an explosion or the impact of a meteorite)

2

: of or relating to a vibration on a celestial body (such as the moon) comparable to a seismic event on earth

3

: having a strong or widespread impact : earthshaking

seismic social changes

seismically

ˈsīz-mi-k(ə-)lē 

adverb

Examples of seismic in a Sentence

Seismic social changes have occurred.

Recent Examples on the Web

Thomas’ double usually gets lost in the shuffle, thanks to Noel’s heroics, or David Fry’s walk-off, or even Thomas’ two seismic swings in the ALDS. —Zack Meisel, New York Times, 13 Sep. 2025

None of their other work, arguably, has had the seismic impact or inspires the same insane quotability as This Is Spinal Tap. —David Fear, Rolling Stone, 12 Sep. 2025

The seismic faultline continues to be active. —M. Rajshekhar, Time, 11 Sep. 2025

Narwhals have exhibited intense fear responses to seismic airguns used in oil and gas exploration, making sudden, deep dives to escape the blasts. —Laura Baisas, Popular Science, 11 Sep. 2025

Word History

Etymology

Greek seismos shock, earthquake, from seiein to shake; probably akin to Avestan thwaēshō fear

First Known Use

1858, in the meaning defined at sense 1

Phrases Containing seismic

• seismic shift

Kids Definition

seismic

adjective

seis·​mic ˈsīz-mik 

ˈsīs-

: of, subject to, or caused by an earthquake or an earth vibration caused by something else (as an explosion)