volcanic

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Of, resembling, or caused by a volcano or volcanoes.
• adjective Produced by or discharged from a volcano.
• adjective Characterized by the presence of volcanoes.
• adjective Powerfully explosive.

from The Century Dictionary.

• Pertaining to or produced by volcanoes or volcanic action: as, volcanic heat, volcanic rock, volcanic phenomena, etc.
• noun In petrography, a volcanic rock: generally used in the plural.

from the GNU version of the Collaborative International Dictionary of English.

• adjective Of or pertaining to a volcano or volcanoes.
• adjective Produced by a volcano, or, more generally, by igneous agencies.
• adjective Changed or affected by the heat of a volcano.
• adjective a mass ejected from a volcano, often of molten lava having a rounded form.
• adjective a hill, conical in form, built up of cinders, tufa, or lava, during volcanic eruptions.
• adjective the subterranean centers of volcanic action; the points beneath volcanoes where the causes producing volcanic phenomena are most active.
• adjective the vitreous form of lava, produced by sudden cooling; obsidian. See Obsidian.
• adjective fetid, sulphurous mud discharged by a volcano.
• adjective rocks which have been produced from the discharges of volcanic matter, as the various kinds of basalt, trachyte, scoria, obsidian, etc., whether compact, scoriaceous, or vitreous.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective Of or pertaining to a volcano or volcanoes; as, volcanic heat.
• adjective Produced by a volcano, or, more generally, by igneous agencies; as, volcanic tufa.
• adjective Changed or affected by the heat of a volcano.
• adjective Reminiscent of a volcano; explosive, violent, full of suppressed anger, energy etc.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adjective relating to or produced by or consisting of volcanoes
• adjective explosively unstable
• adjective igneous rock produced by eruption and solidified on or near the earth's surface; rhyolite or andesite or basalt