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

Our thunderquake study revealed four distinct areas where seismic waves traveled much more slowly than through the surrounding rock. — Nolan Roth, Scientific American, 23 Aug. 2026

This was done using a mixture of radar that measured surface deformation, engineering surveys, boreholes made at the sites, and independent seismic data. — John Timmer, ArsTechnica, 21 Aug. 2026

As Chicago deals with seismic cultural, economic and technological shifts, all 82 library branches will play an even bigger role as anchors for our communities. — Michael Fassnacht, Chicago Tribune, 20 Aug. 2026

While Civil Rights boycotts, like the Montgomery Bus Boycott of 1955 and 1956 led to seismic change, more recent actions have had mixed results, and have worked most noticeably for the political right. — Betty Lin-Fisher, USA Today, 20 Aug. 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)