[1] : The Collaborative International Dictionary of English v.0.48

volcanic \volcan"ic\, a. cf. f. volcanique, it. vulcanico.
   1. of or pertaining to a volcano or volcanoes; as, volcanic
      heat.
      1913 webster

   2. produced by a volcano, or, more generally, by igneous
      agencies; as, volcanic tufa.
      1913 webster

   3. changed or affected by the heat of a volcano.
      1913 webster

   volcanic bomb, a mass ejected from a volcano, often of
      molten lava having a rounded form.

   volcanic cone, a hill, conical in form, built up of
      cinders, tufa, or lava, during volcanic eruptions.

   volcanic foci, the subterranean centers of volcanic action;
      the points beneath volcanoes where the causes producing
      volcanic phenomena are most active.

   volcanic glass, the vitreous form of lava, produced by
      sudden cooling; obsidian. see obsidian.

   volcanic mud, fetid, sulphurous mud discharged by a
      volcano.

   volcanic rocks, 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.
      1913 webster
see also:
volcanic bomb volcanic cone volcanic foci volcanic glass obsidian volcanic mud 
volcanic rocks 

[2] : WordNet (r) 2.0

volcanic
     adj 1: 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"
     2: explosively unstable; "a volcanic temper"
     3: igneous rock produced by eruption and solidified on or near
        the earth's surface; rhyolite or andesite or basalt;
        "volcanic rock includes the volcanic glass obsidian" syn:
         eruptive
see also:
eruptive 

[3] : Moby Thesaurus II by Grady Ward, 1.0

49 moby thesaurus words for "volcanic":
   agitable, bursting, combustible, detonating, edgy, emotional,
   emotionally unstable, eruptive, excitable, explodable, explosible,
   explosive, fierce, fiery, fulminating, furious, hasty,
   high-mettled, high-spirited, high-strung, highly emotional, hot,
   hot-tempered, hotheaded, impetuous, inflammable, irascible,
   irritable, mettlesome, nervous, passionate, peppery, perturbable,
   prickly, quick, quick-tempered, sensitive, short-tempered,
   simmering, skittish, spunky, startlish, stormy, tempestuous,
   tornadic, touchy, vehement, violent, wild

Volcanic >> V Words
Volcanic, definition of term: Volcanic
volcanic_pag1.html

Volcanic Rock >> V Words
Volcanic Rock, definition of term: Volcanic Rock
volcanic+rock_pag1.html

Volcanic Ash >> V Words
Volcanic Ash, definition of term: Volcanic Ash
volcanic+ash_pag1.html

Volcanic Neck >> V Words
Volcanic Neck, definition of term: Volcanic Neck
volcanic+neck_pag1.html