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

This week’s trial is part of an onslaught of legal battles that could have seismic ramifications for Kansas City’s congressional representation. —Kacen Bayless, Kansas City Star, 17 Feb. 2026

The ratios of different seismic waves is consistent with an explosion, said Ben Dando, the head of seismology and verification at NORSAR, a Norwegian organization that watches for possible nuclear tests. —Geoff Brumfiel, NPR, 17 Feb. 2026

The seismic hazards team does geologic mapping. —Graham Womack, Sacbee.com, 15 Feb. 2026

The gesture provoked a seismic reaction internationally while infuriating Olympic officials who claimed Smith and Carlos used the world stage to humiliate their home country. —Los Angeles Times, 14 Feb. 2026

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)