teph·​ra ˈte-frə How to pronounce tephra (audio)
: solid material ejected into the air during a volcanic eruption
especially : ash entry 2 sense 2b

Example Sentences

Recent Examples on the Web Until now, efforts to explain the longevity of Roman concrete have pointed to its use of volcanic tephra—the fragments of rock emitted in an eruption—mined in the Naples area and shipped to construction sites throughout the sprawling Roman empire. WIRED, 3 Feb. 2023 This is likely related to the appearance of a dome in the summit crater of the cone that could collapse to produce the flows of hot ash, tephra, volcanic blocks and gases if the dome gets big enough to reach the edge of the crater (see image below). Erik Klemetti, Discover Magazine, 31 Jan. 2011 The nest location is exposed to continuous, strongly acidic gas emissions (>2.7 ppm of SO2), and sporadic vent clearing episodes that blanket the surrounding area with ash and tephra. Seriously Science, Discover Magazine, 2 Dec. 2016 These inconceivably vast tephra emissions would blacken the atmosphere, diminishing solar radiation and plunging Earth into a global winter; plant growth would suffer and mass extinctions could follow. Stav Dimitropoulos, Popular Mechanics, 16 Dec. 2022 Volcanic ash, a finer form of tephra, consists of tiny, sharp pieces of rock and glass. Zoe Sottile, CNN, 29 Nov. 2022 However, the tephra used in the tomb's mortar contained much more potassium-rich leucite. Jennifer Ouellette, Ars Technica, 17 Feb. 2022 However, the tephra used in the tomb's mortar contained much more potassium-rich leucite. Jennifer Ouellette, Ars Technica, 17 Feb. 2022 The ice cores' tephra, which has a unique geochemical fingerprint, can be used to link the volcanic eruption to an exact volcanic source. David Bressan, Forbes, 3 May 2022 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'tephra.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Word History


New Latin, from Greek, ashes; akin to Sanskrit dahati it burns — more at foment

First Known Use

circa 1944, in the meaning defined above

Time Traveler
The first known use of tephra was circa 1944

Dictionary Entries Near tephra

Cite this Entry

“Tephra.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/tephra. Accessed 8 Feb. 2023.

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