Pronunciation: (vol-kā'nō), [key]
—pl. -noes, -nos.
1. a vent in the earth's crust through which lava, steam, ashes, etc., are expelled, either continuously or at irregular intervals.
2. a mountain or hill, usually having a cuplike crater at the summit, formed around such a vent from the ash and lava expelled through it.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.