Solid matter that is ejected into the air by an erupting volcano. (noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "tephra" in a sentence
"The volcano ejected a minimum of 1.1 km3 of uncompacted tephra, which is equivalent to 0. 20-0.25 km3 of magma or solid rock."
"Fortunately, a detailed 7,000 year record is preserved in peat bogs and lake beds in the form of microscopic layers of volcanic material, including ash, called tephra."
"In the air, after it’s blown out of the volcano, it’s pyroclast—broken rock—but on the ground it’s called tephra."