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

Federal staff also completed an audit in September on an advanced analytical model for seismic assessment. — Aman Tripathi, Interesting Engineering, 3 Oct. 2026

The seismic loss of Helen McCrory led to the final season being rewritten. — Brian Davids, HollywoodReporter, 3 Oct. 2026

Their seismic impact on American and world culture has been well documented. — Matthew Carey, Deadline, 3 Oct. 2026

Ackerman tended to focus on collegial, NCAA and legal issues, prominent during most of her time, as college athletics was swamped with seismic change in recent years. — Dom Amore, Hartford Courant, 1 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)