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

That distance, in the past two years, has come to seem seismic, insurmountable. —Ruth Margalit, New Yorker, 4 Oct. 2025

By the time the five members of Tomorrow X Together (TXT for short) appear, not from the stage but through the pit doors, weaving past the barricades and into the sea of fans, the noise has swelled to seismic levels. —Crystal Bell, Rolling Stone, 3 Oct. 2025

Besides being a hotbed of seismic activity, the Philippines is also among the most climate-vulnerable countries globally, seeing more than 20 typhoons and tropical storm systems yearly. —Chad De Guzman, Time, 2 Oct. 2025

For the Rockies, 79 wins would represent a seismic improvement. —Andy McCullough, New York Times, 1 Oct. 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)