Definitions of volcanic:

  • adjective:   explosively unstable
    Example: "A volcanic temper"
  • adjective:   relating to or produced by or consisting of volcanoes
    Example: "Volcanic steam"
  • adjective:   igneous rock produced by eruption and solidified on or near the earth's surface; rhyolite or andesite or basalt
    Example: "Volcanic rock includes the volcanic glass obsidian"