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

Marshall showed viewers the structural supports of the building that handle gravity loads from the weight of the building and lateral loads due to seismic activity. —Brady MacDonald, Oc Register, 3 Mar. 2026

The result has been a rapid and systematic degradation of Iran’s clout across the Middle East over the past 2½ years, a seismic change that led directly to this weekend’s devastating attacks on Iran by the United States and Israel. —Adam Geller, Fortune, 2 Mar. 2026

Forrest Dein, the co-founder and CMO of Willie’s Remedy, a THC tonic promoted by Willie Nelson, is registering seismic growth since launching the drink less than a year ago. —Joseph Hudak, Rolling Stone, 1 Mar. 2026

Newton’s girls and Douglass’ and Therrell’s boys also earned seismic victories in the round of 16. —Todd Holcomb, AJC.com, 1 Mar. 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)