seis·​mic ˈsīz-mik How to pronounce seismic (audio)
: 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)
: of or relating to a vibration on a celestial body (such as the moon) comparable to a seismic event on earth
: having a strong or widespread impact : earthshaking
seismic social changes
seismically adverb

Example Sentences

Seismic social changes have occurred.
Recent Examples on the Web Scientists believe that the chamber may also be key to understanding the seismic activity in this region. Elinda Labropoulou, CNN, 26 Apr. 2023 To shield the balance from the outside world, the physicists needed a site with as little seismic activity as possible—hence Sardinia. Manon Bischoff, Scientific American, 24 Apr. 2023 The Polar Earth Observing Network (PoleNet) has deployed and maintained dozens of GPS and seismic stations to monitor the behavior of West Antarctic glaciers. Bymarissa Grunes,, 20 Apr. 2023 The warehouse and purchasing building would get a roof replacement alongside seismic and structural upgrades, costing about $4.1 million. Morgan Krakow, Anchorage Daily News, 14 Mar. 2023 And so now, down by 12, with all that was at stake, the Hoosiers were on the brink of a seismic collapse. Tyler Tachman, The Indianapolis Star, 6 Mar. 2023 Jackson hopes that Sunday's 30th anniversary serves as a reminder that even though decades have passed since the seismic acts of terrorism in the United States' most populous city, no one, anywhere, can say the threat of mass violence is over. Jennifer Peltz, Hartford Courant, 26 Feb. 2023 This metallic inner core, about 1,500 miles (2,440) wide, was discovered in the 1930s, also based on seismic waves traveling through Earth. Reuters, NBC News, 24 Feb. 2023 Antakya, the regional capital of Hatay province on the border with Syria, suffered some of the worst devastation wrought by Monday’s seismic shocks. Jared Malsin, WSJ, 8 Feb. 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'seismic.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


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

Time Traveler
The first known use of seismic was in 1858

Dictionary Entries Near seismic

Cite this Entry

“Seismic.” Dictionary, Merriam-Webster, Accessed 28 May. 2023.

Kids Definition


seis·​mic ˈsīz-mik How to pronounce seismic (audio)
: of, subject to, or caused by an earthquake or an earth vibration caused by something else (as an explosion)

More from Merriam-Webster on seismic

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