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 Chiefs at least discussed, even if briefly, that sort of seismic change. — Sam McDowell 16, Kansas City Star, 16 Oct. 2026

Why did the songs still feel seismic even with such relatively low mainstream profiles? — Andrew Unterberger, Billboard, 15 Oct. 2026

According to The Irish Times, Rooney’s seismic breakout, Normal People, sold more than a million copies in the UK. — Brittany Allen, Literary Hub, 14 Oct. 2026

On Earth, about 90 percent of all seismic activity occurs near the boundaries between lithospheric plates. — Andrew Paul, Popular Science, 14 Oct. 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)