The Collaborative International Dictionary of English v.0.48:

Imperial \Im*pe"ri*al\, a. [OE. emperial, OF. emperial, F.
   imp['e]rial, fr. L. imperialis, fr. imperium command,
   sovereignty, empire. See Empire.]
   1. Of or pertaining to an empire, or to an emperor; as, an
      imperial government; imperial authority or edict.
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            The last
            That wore the imperial diadem of Rome. --Shak.
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   2. Belonging to, or suitable to, supreme authority, or one
      who wields it; royal; sovereign; supreme. "The imperial
      democracy of Athens." --Mitford.
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            Who, as Ulysses says, opinion crowns
            With an imperial voice.               --Shak.
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            To tame the proud, the fetter'd slave to free,
            These are imperial arts, and worthy thee. --Dryden.
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            He sounds his imperial clarion along the whole line
            of battle.                            --E. Everett.
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   3. Of superior or unusual size or excellence; as, imperial
      paper; imperial tea, etc.
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   Imperial bushel, gallon, etc. See Bushel, Gallon,
      etc.

   Imperial chamber, the, the sovereign court of the old
      German empire.

   Imperial city, under the first German empire, a city having
      no head but the emperor.

   Imperial diet, an assembly of all the states of the German
      empire.

   Imperial drill. (Manuf.) See under 8th Drill.

   Imperial eagle. (Zool.) See Eagle.

   Imperial green. See Paris green, under Green.

   Imperial guard, the royal guard instituted by Napoleon I.


   Imperial weights and measures, the standards legalized by
      the British Parliament.
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