- enPR: /mĕtŏnĭk sīkl/
- MEH-toh-nik saikl
- (astronomy, calendar studies) A particular approximate common multiple of the tropical year and the synodic month; in other words, the 19-year period over which the lunar phases occur on the same dates.
- According to the Metonic cycle, a lunar calendar begins on the same solar date every 19 years.
- (less exact 8-year cycle): octaeteris