adj. & n.
adj. 1 of or characteristic of an empire or comparable sovereign State. 2 a of or characteristic of an emperor. b supreme in authority. c majestic, august. d magnificent. 3 (of non-metric weights and measures) used or formerly used by statute in the UK (imperial gallon).
n. a former size of paper, 762 x 559 mm (30 x 22 inches). imperially adv.
[ ME f. OF f. L imperialis f. imperium command, authority ]