Definition of volcanic

• relating to or produced by or consisting of volcanoes; "volcanic steam"; "volcanic islands such as Iceland"; "a volcanic cone is a conical mountain or hill built up of material from volcanic eruptions"
• explosively unstable; "a volcanic temper"
• igneous rock produced by eruption and solidified on or near the earths surface; rhyolite or andesite or basalt; "volcanic rock includes the volcanic glass obsidian"