Webster’s Revised Unabridged Dictionary · 1913
Metemptosis
Met′emp·to′sis (mĕt′ĕmp·tō′sĭs), n. [NL., from Gr. μετά beyond, after + ἔμπτωσις a falling upon, fr. ἐμπέπτειν to fall in or upon; ἐν in + πίπτειν to fall.] (Chron.) The suppression of a day in the calendar to prevent the date of the new moon being set a day too late, or the suppression of the bissextile day once in 134 years. The opposite to this is the proemptosis, or the addition of a day every 330 years, and another every 2,400 years.