Source : Webster's Revised Unabridged Dictionary (1913)

Igneous \Ig"ne*ous\, a. [L. igneus, fr. ignis fire; allied to
   Skr. agni, Lith. ugnis, OSlav. ogne.]
   1. Pertaining to, having the nature of, fire; containing
      fire; resembling fire; as, an igneous appearance.

   2. (Geol.) Resulting from, or produced by, the action of
      fire; as, lavas and basalt are igneous rocks.

Source : WordNet®

igneous
     adj 1: produced under conditions involving intense heat; "igneous
            rock is rock formed by solidification from a molten
            state; especially from molten magma"; "igneous fusion
            is fusion by heat alone"; "pyrogenic strata" [syn: {pyrogenic},
             {pyrogenous}]
     2: like or suggestive of fire; "the burning sand"; "a fiery
        desert wind"; "an igneous desert atmosphere" [syn: {fiery}]