1. Of, resembling, or caused by a volcano or volcanoes: a volcanic peak; volcanic islands.
2. Produced by or discharged from a volcano: volcanic ash.
3. Characterized by the presence of volcanoes.
4. Powerfully explosive: a volcanic temper.

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.