ejecta
Americannoun
plural noun
Etymology
Origin of ejecta
1885–90; neuter plural of Latin ējectus. See eject
Explanation
Ejecta is the scientific term for material that is thrown or forced out due to an eruption, explosion, or impact. When a star explodes, the matter that is thrown out from the center is called ejecta. A volcano casts out molten ejecta in the form of lava bombs. Other volcanic ejecta includes ash, dust, and rock fragments. When a large meteorite from space hits Earth's surface, the impact sends a spray of pulverized rock and debris outwards. That ejecta settles around a newly created crater. Human activity can create ejecta, too. When bombs are detonated, massive amounts of ejecta in the form of soil and rock fragments are displaced and launched outward and upward.
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
What Enceladus does is akin to a volcano hurling lava into space -- except the ejecta are plumes of water vapor and ice.
From Science Daily • Nov. 10, 2025
"We actually used the equations of volcanoes to predict how fast ejecta would fly - 90 meters per second," he told BBC News.
From BBC • Nov. 18, 2023
The supernova’s ejecta expands in an “hourglass shape” as it impacts this disk.
From Scientific American • Jul. 21, 2023
But then sometime between day 200 and 1000 the ejecta must have clashed with the hollow ring of star stuff, causing it to light up again.
From Space Scoop • Mar. 21, 2023
Lots of carbon comes up with kimberlite ejecta, but most is vaporized or turns to graphite.
From "A Short History of Nearly Everything" by Bill Bryson
![]()
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.