noun
sixteen-day-old moon; moon on the sixteenth night of the lunar month
Refers to the moon on the night after the full moon (fifteenth night). In the lunar calendar, the moon rises later each night, so the 十六夜 moon appears later than the full moon. Often used in poetic or traditional contexts.
十六夜の月は、満月の翌日に見られる少し欠けた月です。
The sixteen-day-old moon is a slightly waning moon seen the day after the full moon.
旧暦の八月十六夜の月を「十六夜」と呼びます。
The moon on the sixteenth night of the eighth month in the lunar calendar is called 'izayoi'.
十五夜 refers to the night of the full moon (fifteenth night), often associated with moon-viewing festivals. 十六夜 is the next night.
The reading いざよい is a native Japanese word. The kanji 十六夜 literally mean 'sixteen night', matching the meaning. The historical derivation of the reading is uncertain.