tephra

American  

[tef-ruh] / ˈtɛf rə /

noun

(used with a plural verb)

1. clastic volcanic material, as scoria, dust, etc., ejected during an eruption.

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tephra British  

/ ˈtɛfrə /

noun

1. solid matter ejected during a volcanic eruption

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tephra Scientific  

/ tĕf′rə /

1. 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.

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Etymology

Origin of tephra

First recorded in 1960–65, tephra is from the Greek word téphra (singular) ashes

Explanation

Tephra is the scientific term for the solid fragments that shoot into the air when a volcano erupts. Tephra, which volcano experts also refer to as pyroclasts, refers to anything solid among the materials that are ejected during a volcanic eruption. In addition to gas and molten lava, tephra spews out in the form of ash, chunks of rock, glass, and cinders. Over time, tephra can accumulate in thick layers that eventually compact into solid rock. The Greek word tephra means "ash."

Example Sentences

Each volcanic eruption produces tephra with a distinct chemical signature.

From Science Daily • May 11, 2026

Roman concrete consisted of a mixture of a white powder known as slaked lime, small particles and rock fragments called tephra ejected by volcanic eruptions, and water.

From Science Magazine • Jan. 5, 2023

Traces of tephra recall the 1815 eruption of Indonesia’s Mount Tambora, which cast a pall of bleak weather over Europe.

From Washington Post • Apr. 7, 2021

McConnell and the other researchers made the discovery in 2019 when they came upon "an unusually well-preserved layer of tephra in an ice core sample" and investigated further.

From Fox News • Jun. 23, 2020

The largest has curdled into a pillar like the cloud of tephra and ash and steam that billows atop an erupting volcano.

From "All the Light We Cannot See" by Anthony Doerr