The Collaborative International Dictionary of English v.0.48:

Embassy \Em"bas*sy\, n.; pl. Embassies. [OF. ambass['e]e,
   embasc['e]e, LL. ambasciata, fr. ambasciare for ambactiare to
   go on a mission, fr. L. ambactus vassal, dependent, of Celtic
   or German origin; cf. W. amaeth husbandman, Goth. andbahts
   servant, G. amt office, OHG. ambaht. Cf. Ambassador.]
   1. The public function of an ambassador; the charge or
      business intrusted to an ambassador or to envoys; a public
      message to; foreign court concerning state affairs; hence,
      any solemn message.
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            He sends the angels on embassies with his decrees.
                                                  --Jer. Taylor.
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   2. The person or persons sent as ambassadors or envoys; the
      ambassador and his suite; envoys.
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   3. The residence or office of an ambassador.
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   Note: Sometimes, but rarely, spelled ambassy.
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