Calippic \Ca*lip"pic\, a. Of or pertaining to Calippus, an Athenian astronomer.

Calippic period, a period of seventy-six years, proposed by Calippus, as an improvement on the Metonic cycle, since the 6940 days of the Metonic cycle exceeded 19 years by about a quarter of a day, and exceeded 235 lunations by something more.

Source: Webster's Revised Unabridged Dictionary (1913)