noun
night of waiting for someone
Archaic term for a night spent waiting for a person who is expected to come. Often used in classical poetry and literature.
待宵の月が雲間に隠れた。
The moon of the waiting night hid behind the clouds.
noun
night of the 14th day of the 8th lunar month
Archaic term for the night before the full moon of the 8th lunar month, associated with moon-viewing traditions.
旧暦八月十四日の夜を待宵と呼んだ。
The night of the 14th day of the 8th month of the old calendar was called matsuyoi.
Compound of 待つ (matsu, 'to wait') and 宵 (yoi, 'early night'). The exact historical derivation is uncertain, but the term is associated with classical poetic usage.