obsidian
Americannoun
noun
Etymology
Origin of obsidian
First recorded in 1350–1400; from Latin Obsidiānus, printer's error for Obsiānus “pertaining to Obsius,” the discoverer (according to Pliny) of a similar mineral in Ethiopia; replacing Middle English obsianus, from Latin
Explanation
Obsidian is a type of black or dark glass formed from cooling lava. So if you find a shiny, hard, dark piece of glass next time you’re hanging around a volcano, it’s probably a piece of obsidian. The word obsidian essentially means “stone of Obsius.” So who was Obsius? According to an ancient Roman writer, he was the guy who first found this type of stone in Ethiopia. You’ll find obsidian used as a modifier a lot. Think of an obsidian arrowhead, blade or mirror. Sometimes it is used as a fancy way of describing people’s eyes in romance novels as in, “Her eyes were dark and shining, two obsidian orbs.”
Vocabulary lists containing obsidian
The Lightning Thief
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Black and Gray
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Earth Science - Middle School
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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.
On Earth, volcanic glass such as obsidian is an example of silica-rich material.
From Science Daily ● Oct. 7, 2026
Elordi strides naturally through the film’s burning-of-Atlanta orange sunscapes and its grasslands stabbed by obsidian spikes of rock.
From Los Angeles Times ● Feb. 11, 2026
From precolonial Mexico we discover obsidian mirrors used for divination in Mayan and Aztec ceremonies.
From The Wall Street Journal ● Jan. 16, 2026
Like obsidian, in fact, their edges are sharp but the shards have an almost twirly shape and lack the crystalline structure of black-colored minerals like augite or tourmaline.
From Salon ● Mar. 4, 2025
The slab, which had become a chair, was obsidian black.
From "We Are the Ants" by Shaun David Hutchinson
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.
