c. 1600, of or pertaining to Dionysos (Latin Dionysus), Greek god of wine and revelry, identified with Roman Bacchus. His name is of unknown origin. In some cases a reference to historical men named Dionysius, such as the two tyrants of that name of Syracuse, both notorious for cruelty, or Dionysius Exiguus, 6th c. Scythian monk who invented the Anno Domini era (see A.D.). The reference is to him in Dionysian period, a measure of 532 Julian years, at the end of which the full moons recur on the same days of the year.
updated on August 22, 2018