Source : Webster's Revised Unabridged Dictionary (1913)

Erratic \Er*rat"ic\, a. [L. erraticus, fr. errare to wander: cf.
   F. erratique. See {Err}.]
   1. Having no certain course; roving about without a fixed
      destination; wandering; moving; -- hence, applied to the
      planets as distinguished from the fixed stars.

            The earth and each erratic world.     --Blackmore.

   2. Deviating from a wise of the common course in opinion or
      conduct; eccentric; strange; queer; as, erratic conduct.

   3. Irregular; changeable. ``Erratic fever.'' --Harvey.

   {Erratic blocks}, {gravel, etc.} (Geol.), masses of stone
      which have been transported from their original resting
      places by the agency of water, ice, or other causes.

   {Erratic phenomena}, the phenomena which relate to
      transported materials on the earth's surface.