The Collaborative International Dictionary of English v.0.48:

Poll \Poll\, n. [Akin to LG. polle the head, the crest of a
   bird, the top of a tree, OD. pol, polle, Dan. puld the crown
   of a hat.]
   1. The head; the back part of the head. "All flaxen was his
      poll." --Shak.
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   2. A number or aggregate of heads; a list or register of
      heads or individuals.
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            We are the greater poll, and in true fear
            They gave us our demands.             --Shak.
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            The muster file, rotten and sound, upon my life,
            amounts not to fifteen thousand poll. --Shak.
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   3. Specifically, the register of the names of electors who
      may vote in an election.
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   4. The casting or recording of the votes of registered
      electors; as, the close of the poll.
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            All soldiers quartered in place are to remove . . .
            and not to return till one day after the poll is
            ended.                                --Blackstone.
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   5. pl. The place where the votes are cast or recorded; as, to
      go to the polls.
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   6. The broad end of a hammer; the but of an ax.
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   7. (Zool.) The European chub. See Pollard, 3
      (a) .
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   Poll book, a register of persons entitled to vote at an
      election.

   Poll evil (Far.), an inflammatory swelling or abscess on a
      horse's head, confined beneath the great ligament of the
      neck.

   Poll pick (Mining), a pole having a heavy spike on the end,
      forming a kind of crowbar.

   Poll tax, a tax levied by the head, or poll; a capitation
      tax.
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WordNet (r) 3.0 (2006):

poll tax
    n 1: a tax of a fixed amount per person and payable as a
         requirement for the right to vote