Vol-cān'ic, a.
a. [Fr. volcanique, vulcanique, Sp. volcanico, It. vulcanico.]
- Of, or pertaining to, a volcano, or to volcanoes; as, volcanic heat.
- Produced by a volcano; as, volcanic tufa.
- Changed or affected by the heat of a volcano.
Volcanic bomb, a detached mass of melted matter thrown out of a volcano, and assuming, as it falls, a rounded shape, or sometimes elongated like a pear.—Volcanic foci, the subterranean centers of volcanic action; the points beneath volcanoes where the causes producing volcanic phenomena are most active.—Volcanic glass (Min.), a mineral resembling glass, formed from lava by its sudden cooling; obsidian. See Obsidian.—Volcanic rocks (Geol.), rocks which have been produced from the discharges of volcanic matter, as the various kinds of trachyte, scoria, obsidian, and other lavas, whether vitreous, compact, or scoriaceous. Craig.