Regal
Part of speech: adjective
Definition: Of or having to do with royalty. Befitting a king, queen, emperor, or empress.
Imperial
Part of speech: adjective
Definition: Related to an empire, emperor, or empress.Relating to the British imperial system of measurement.Very grand or fine.Of special, superior, or unusual size or excellence.
Part of speech: noun
Definition: A bottle of wine (usually Bordeaux) containing 6 liters of fluid, eight times the volume of a standard bottle.A printing-paper size measuring 30 inches x 22 inches.
Example sentence: There are occasionally eureka moments - off the top of my head, maybe Darth Vader's theme, you know, the imperial march.