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 recent seismic activity was much milder than last year’s magnitude 4.8 earthquake, which originated on a New Jersey fault line and rippled through the Big Apple. —Muri Assunção, New York Daily News, 5 Aug. 2025

His impact was seismic and remained so until his death five years later, in May of 1997, while swimming fully clothed in the Mississippi River. —Tony Gervino, HollywoodReporter, 5 Aug. 2025

In a study published on July 30 in the journal Science Advances, geophysicists examined the Apollo 17 landing site in the moon's Taurus-Littrow valley — where astronauts last set foot on the moon in 1972 — to understand how seismic activity has shaped the landscape. —Sharmila Kuthunur, Space.com, 4 Aug. 2025

Volcanic and seismic activity are common at the boundaries of such plates. —Chad De Guzman, Time, 4 Aug. 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)