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

As Grand Slams keep racking up attendance records, the first of the year has made a small decision that could prove to be a seismic one. — James Hansen, New York Times, 27 July 2026

The news of Downey’s return to the MCU was seismic on the ground while inspiring a myriad of takes on the state of Marvel since. — Savannah Salazar, Vulture, 26 July 2026

Now, after a seismic offseason trade to the Los Angeles Rams, the superstar pass rusher has decided to hand over the keys to his Buckeye State residence. — Wendy Bowman, Robb Report, 25 July 2026

Michael Schmitz, a geophysicist professor at Simon Bolivar University in Caracas, participated in a study that ran from 2004-2009 on microzones in Caracas, subdivisions of the region based on seismic risk. — Syra Ortiz-Blanes, Miami Herald, 24 July 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)