The Collaborative International Dictionary of English v.0.48:

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.
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            The earth and each erratic world.     --Blackmore.
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   2. Deviating from a wise of the common course in opinion or
      conduct; eccentric; strange; queer; as, erratic conduct.
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   3. Irregular; changeable. "Erratic fever." --Harvey.
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   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.
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