The Collaborative International Dictionary of English v.0.48:

Overflow \O`ver*flow"\, v. t. [imp. & p. p. Overflowed; p. pr.
   & vb. n. Overflowing.] [AS. oferfl?wan. See Over, and
   Flow.]
   1. To flow over; to cover woth, or as with, water or other
      fluid; to spread over; to inundate; to overwhelm.
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            The northern nations overflowed all Christendom.
                                                  --Spenser.
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   2. To flow over the brim of; to fill more than full.
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