The Collaborative International Dictionary of English v.0.48:

Placet \Pla"cet\, n. [L. placet it pleases.]
   1. A vote of assent, as of the governing body of a
      university, of an ecclesiastical council, etc.
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   2. The assent of the civil power to the promulgation of an
      ecclesiastical ordinance. --Shipley.
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            The king . . . annulled the royal placet. --J. P.
                                                  Peters.
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