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

It’s been a busy time for UCF athletics director Terry Mohajir, who has been working through the seismic changes associated with the college landscape due to the NCAA v House settlement. —Matt Murschel, The Orlando Sentinel, 11 July 2025

The seismic activity was similar to those caused by the initial slipping between rock and ice that preceded large avalanches on the volcano in the past, according to the AVO. —ABC News, 11 July 2025

Tariffs are far from the only seismic changes that have caused Joas to pivot. —Jan Ellen Spiegel, Hartford Courant, 7 July 2025

This past week, Congress passed seismic legislation widely expected to benefit the rich and decimate the poor. —Alison Foreman, IndieWire, 4 July 2025

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)