Obsidian

Part of speech: noun

Pronunciation: /ˌɒbˈsɪd.i.ən/

Definitions

  1. A dark volcanic glass formed when lava cools rapidly, typically black and smooth with sharp edges when broken
  2. A lustrous volcanic rock composed of cooled lava that appears glassy and dark, prized for its razor-sharp fractured edges and use in tools and ornaments
  3. A natural glass-like mineral substance created by rapid cooling of molten rock, characterized by its deep black coloration and keen cutting properties when fractured

Etymology: Obsidian entered English in the 16th century as a borrowed term from Latin "obsidianus", which itself derived from "obsidian", a word attributed to Pliny the Elder in his natural histories. The Latin term was believed to come from a personal name—specifically, a man named Obsius who was said to have discovered this volcanic glass in Ethiopia. This etymology, preserved in Pliny's account, reflects the Roman practice of naming materials and substances after their discoverers or the places associated with their first identification. The name thus carries within it a piece of ancient commercial and geological history, linking the substance to its reputed first observer. The physical substance itself—a naturally occurring volcanic glass formed from the rapid cooling of lava—has been used by humans for tens of thousands of years, particularly in Mesoamerica and the Mediterranean. The Romans valued it highly for mirrors, vessels, and ornamental objects, and their extensive use of the material ensured that the Latin name became the standard term across European languages. When English speakers encountered the substance during the Renaissance and early modern period, they adopted the Latin name wholesale rather than coining a new native English term. In English, obsidian has remained relatively stable in its core meaning: the hard, glassy volcanic rock itself. The adjective use developed naturally from the noun, describing things that resemble obsidian in appearance—typically dark, glossy, and smooth. The word carries no metaphorical weight in modern English beyond these literal descriptive applications, making it a straightforward case of a classical term that entered the language and remained unchanged in both form and essential meaning.

Synonyms: volcanic glass, igneous rock