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

The epicenter of the earthquake, one of the strongest recorded by modern seismic instruments, according to the Earth Observatory, was about 240 kilometers (150 miles) south of the volcano. —Hannah Millington, MSNBC Newsweek, 21 Nov. 2025

Which isn’t to say that the eventual meeting of the minds won’t be colored by at least one seismic upheaval, as the YouTubes and Netflixes flex their zillion-dollar market caps in a bid to unseat one of the NFL’s loyal TV partners. —Anthony Crupi, Sportico.com, 21 Nov. 2025

The team behind the observation believes their findings will help to clarify long-standing questions related to these seismic events. —Chris Young, Interesting Engineering, 13 Nov. 2025

The researchers collected seismic data on 27 faults below Turkana, looking back over the course of the past 10,000 years—a time horizon that saw a lot of changes in East Africa. —Jeffrey Kluger, Time, 12 Nov. 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)