from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A usually black or banded, hard volcanic glass that displays shiny, curved surfaces when fractured and is formed by rapid cooling of lava.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. a type of black glass produced by volcanos
- adj. black
from the GNU version of the Collaborative International Dictionary of English
- n. A kind of glass produced by volcanoes. It is usually of a black color, and opaque, except in thin splinters.
from The Century Dictionary and Cyclopedia
- n. A volcanic rock, in a vitreous condition, and closely resembling ordinary bottle-glass in appearance and texture.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. acid or granitic glass formed by the rapid cooling of lava without crystallization; usually dark, but transparent in thin pieces
Latin obsidiānus, misreading of obsiānus (lapis), Obsian (stone), obsidian, after Obsius, a Roman who supposedly discovered it or a similar mineral.(American Heritage® Dictionary of the English Language, Fourth Edition)