English Reference

Word

obsidian

Phoneticsob·sid·i·an

US/əbˈsɪdiən/

UK/ɒbsˈɪdiən/

Definition

n. a shiny black rock that is actually a type of glass. It forms when lava cools very quickly and is used to make sharp tools or jewelry.

n. a naturally occurring volcanic glass formed by the rapid cooling of lava from a volcanic eruption. It is typically black in color and possesses a smooth, glassy surface.

Examples

“The ancient people used obsidian to make very sharp knives.”

“Archaeologists found a shard of obsidian at the site, suggesting that the inhabitants traded with distant volcanic regions.”

“The polished surface of the obsidian mirror reflected the room with such clarity that it seemed to disappear into the darkness of the stone.”

Examples

simple

“The ancient people used obsidian to make very sharp knives.”

contextual

“Archaeologists found a shard of obsidian at the site, suggesting that the inhabitants traded with distant volcanic regions.”

complex

“The polished surface of the obsidian mirror reflected the room with such clarity that it seemed to disappear into the darkness of the stone.”

Real-World Examples

“For decades, archaeologists have been uncovering rare and mysterious incised obsidian arrowheads across Neolithic Central Anatolia, each one bearing a unique design etched into its glassy black surface nearly 9,000 years ago.”
Phys.org · 21 Aug 2026
“Their archaeological sites contain turquoise, southwestern-style pottery, and obsidian from hundreds of kilometers to the west.”
Ars Technica · 27 Aug 2026

Etymology

From Latin obsidianus; named after Obsidius, who was, according to Pliny, the Roman who discovered the stone in Aethiopia.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry

Level
C1 · Advanced
Frequency
Occasional
Updated

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English Reference