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[tef-ruh] /ˈtɛf rə/
noun, (used with a plural verb)
clastic volcanic material, as scoria, dust, etc., ejected during an eruption.
Origin of tephra
1960-65; < Greek téphra (singular) ashes Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the web for tephra
  • The slope's top layer is crumbly tephra, sometimes as big as charcoal briquettes.
  • Eruptive behavior has varied from vigorous explosions, accompanied by tephra falls and pyroclastic flows, to effusive lava flows.
  • The heavy tephra fall caused severe property damage a few days after the onset of the eruption.
  • tephra ingested by vehicle engines can clog filters and increase wear.
  • Initial explosive eruptions produced small pyroclastic flows and tephra fallout from several aligned vents low on the south flank.
  • Beyond the volcano, outcrops expose sections of a series of andesitic and basaltic tephra-fall deposits.
  • tephra plumes block sunlight, sometimes causing total darkness even at midday.
  • tephra can range in size from tiny particles of ash to house-size boulders.
  • Volcanologists use the term tephra for such fragments, which range in size from microscopic ash to meter-sized blocks.
  • It had not previously been described as a tephra type.
British Dictionary definitions for tephra


(mainly US) solid matter ejected during a volcanic eruption
Word Origin
C20: Greek, literally: ashes
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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tephra in Science
Solid matter, such as ash, dust, and cinders, that is ejected into the air by an erupting volcano. Tephra is a general term for all pyroclastic materials ejected from a volcano.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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