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 heritage building received extensive structural and seismic upgrades, as well as restoration of its masonry, windows, timber structure and major interior spaces. — New Atlas, 23 Sep. 2026

Perhaps, with opinion polls signaling a seismic snap in the other direction and economic conditions on the Great Plains so dismal, the Republican hold on rural America is loosening. — Kyle Paoletta, Harpers Magazine, 22 Sep. 2026

There is a seismic opportunity for research teams around the world to join forces to evaluate how social media and its restrictions impact youth mental health. — Camilla Iannone, STAT, 22 Sep. 2026

Ultimately, the current and upcoming projects to address seismic safety are expected to cost more than $2 billion. — Andrew J. Campa, Los Angeles Times, 20 Sep. 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)