seismic

adjective

seis·​mic ˈsīz-mik How to pronounce seismic (audio)
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 How to pronounce seismic (audio)
adverb

Examples of seismic in a Sentence

Seismic social changes have occurred.
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Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
This pattern ultimately helped the organization issue alerts when eruptions were likely to occur, which was especially useful because there were no clear seismic signals immediately before fountains restarted. — John Timmer, ArsTechnica, 9 Oct. 2026 Those seismic changes are such a strange thing to go through. — Ashley Spencer, Los Angeles Times, 8 Oct. 2026 From the lunar surface, GIMLI will gather data using ground-penetrating radar, seismic sensors and a gravimeter to better understand what's really happening underneath the surface. — Chelsea Gohd, Space.com, 8 Oct. 2026 Though a seismic best-seller, publishers have struggled to replicate that cultural event. — Brittany Allen, Literary Hub, 8 Oct. 2026 See All Example Sentences for seismic

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

Time Traveler
The first known use of seismic was in 1858

Phrases Containing seismic

Browse Nearby Words

seismetic
seismic
seismicity
See all Nearby Words

Cite this Entry

“Seismic.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/seismic. Accessed 14 Oct. 2026.

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Kids Definition

seismic

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