Ecclesiastical equinox

Paschal full moon

The paschal full moon is the particular 'ecclesiastical full moon' that is used in the calculation of the date of Easter. The name paschal is derived from Pascha, a transliteration of the Aramaic word meaning Passover. This 'paschal full moon' is the one that falls on or after March 21. (March 21 is the ecclesiastical equinox, the date fixed by the Gregorian reform of the calendar as a fixed reference date for the March equinox in the Northern hemisphere; the actual Equinox can fall on March 19, 20 or 21). The date of Easter is determined as the first Sunday after that specific full moon. This "full moon" does not necessarily correspond directly to any astronomical event, but is instead the 14th day of a lunar month, determined from tables. It may differ from the date of the actual full moon by up to two or even three days.