(im·pir′ē·əl) adjective
1. Of or pertaining to an empire, or to an emperor or an empress.
2. Designating the legal weights and measures of the United Kingdom.
3. Of or pertaining to a state as supreme over colonies or the like.
4. Possessing commanding power or dignity; predominant.
5. Superior in size or quality.
—noun
1. A pointed tuft of hair on the chin: from the emperor Napoleon III, who wore such a beard.
2. Anything of more than usual size of the class to which it belongs, or of superior excellence.
3. A size of paper: in the United States, 23 in. × 31 in.; in Great Britain, 22 in. × 30 in.
4. A size of slate 24 inches wide and from 12 to 30 inches long.
5. A former Russian gold coin worth 15 rubles.
6. The top of a carriage, as of a diligence. [<OF <L imperialis <imperium rule]
—im·pe′ri·al·ly adverb Synonyms (adj.): exalted, grand, kingly, magnificent, majestic, noble, queenly, regal, royal, sovereign, supreme. Antonyms: base, beggarly, cowering, cringing, ignoble, inferior, mean, paltry, poor, servile, slavish.

(im·pir′ē·əl) noun
An adherent or soldier of the Holy Roman Empire.