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

While not a household name like the San Andreas, the Elsinore fault is part of a larger seismic zone that experts fear and believe more people should know about. —Alyssa Bereznak, Los Angeles Times, 19 Apr. 2025

Rendering seismic reflection images from the readings, the paper authors identified the chamber’s top and contents. —Sam Walters, Discover Magazine, 17 Apr. 2025

Here, a patchy pattern of material with that same high seismic velocity sagged to a depth of nearly 600 kilometers, almost to the lower mantle. —Meghan Bartels, Scientific American, 17 Apr. 2025

The ruling sets up a seismic legal showdown between an unrelenting judge and a defiant Trump administration, which has prioritized following the president’s executive directives over a flurry of judicial mandates. —David Catanese, Miami Herald, 16 Apr. 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)