Metonic cycle

[ mi-ton-ik ]
/ mɪˈtɒn ɪk /

noun Astronomy.

a cycle of 235 synodic months, very nearly equal to 19 years, after which the new moon occurs on the same day of the year as at the beginning of the cycle with perhaps a shift of one day, depending on the number of leap years in the cycle.


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Origin of Metonic cycle

1880–85; named after Meton, 5th-century b.c. Athenian astronomer; see -ic Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

British Dictionary definitions for metonic cycle

Metonic cycle
/ (mɪˈtɒnɪk) /


a cycle of nearly 235 synodic months after which the phases of the moon recur on the same days of the yearSee also golden number

Word Origin for Metonic cycle

C17: named after Meton, 5th-century bc Athenian astronomer
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012