By cock and pie

from The Collaborative International Dictionary of English v.0.48
Pie \Pie\, n. [F. pie, L. pica; cf. picus woodpecker, pingere to
   paint; the bird being perhaps named from its colors. Cf.
   {Pi}, {Paint}, {Speight}.]
   1. (Zool.)
      (a) A magpie.
      (b) Any other species of the genus {Pica}, and of several
          allied genera. [Written also {pye}.]
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   2. (R. C. Ch.) The service book.
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   3. (Pritn.) Type confusedly mixed. See {Pi}.
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   {By cock and pie}, an adjuration equivalent to "by God and
      the service book." --Shak.

   {Tree pie} (Zool.), any Asiatic bird of the genus
      {Dendrocitta}, allied to the magpie.

   {Wood pie}. (Zool.) See {French pie}, under {French}.
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