Seismic means to do with earthquakes and the shaking of the ground. Seismic waves spread out from the point where a fault slips, and a seismometer draws them as a jagged line running across the paper.
You meet the word most in seismic activity, the tremors large and tiny that instruments pick up all day whether or not anybody feels them. Oil and gas companies run a seismic survey, thumping the ground on purpose and reading what lies underneath from the echoes that come back. Then there is the borrowed sense, now the commonest of the lot in newspapers: a seismic shift, a seismic change, a result described as seismic, where it means enormous and unsettling, everything rearranged at once. The whole family starts with seismo-: seismology, seismograph, seismometer.
1adjectiveseismicTo do with earthquakes and the movement of the ground.
“Seismic waves from the quake were recorded on the other side of the world.”
2nounactivitySeismic activity: the movement and shaking inside the earth, from tremors too small to feel up to full earthquakes.
“Seismic activity under the volcano increased for a week before the eruption.”
3adjectivemomentousHuge in effect; changing everything at once.
“The vote brought a seismic change in the way the party is run.”
synonyms: momentous, earth-shattering
SEISmic → why the ground moves under JAPAN
Japan sits where two plates meet, which is why the ground there moves so often. Seismic is anything to do with that movement.
hooks ontoground
Ancient Greek σεισμός (seismos) meant a shaking, an earthquake. English took it, bolted on the ending -ic, and had an adjective for anything to do with ground that moves. The same Greek word supplies the seismo- at the front of seismograph and seismology. So when a newspaper calls a result seismic, it is still saying that the ground moved.
Ancient Greek
σεισμός — shaking, earthquake
English, today
seismic
Based on Ancient Greek σεισμός (“shaking, earthquake”) + -ic, equivalent to seismo- + -ic.
Etymology from Wiktionary, CC BY-SA
Practised in Science & Space