The Collaborative International Dictionary of English v.0.48:

Pica \Pi"ca\, n. [L. pica a pie, magpie; in sense 3 prob. named
   from some resemblance to the colors of the magpie. Cf. Pie
   magpie.]
   1. (Zool.) The genus that includes the magpies.
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   2. (Med.) A vitiated appetite that craves what is unfit for
      food, such as clay, chalk, ashes, coal, etc.;
      chthonophagia.

   Syn: allotriophagy.
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   3. (R. C. Ch.) A service-book. See Pie. [Obs.]
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   4. (Print.) A size of type next larger than small pica, and
      smaller than English.
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   Note: Pica is twice the size of nonpareil, and is used as a
         standard of measurement in casting leads, cutting
         rules, etc., and also as a standard by which to
         designate several larger kinds of type, as double pica,
         two-line pica, four-line pica, and the like.
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   Small pica (Print.), a size of type next larger than long
      primer, and smaller than pica.
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