the declaration of night time via a rooster's crow

polar night

(Internet slang, humorous, pun) Christmas Eve, as a night of sexual activity between young couples

(euphemistic) job in the nightlife / sex industry

unpredictable; no one knows what the future holds.

Eggcorn of 一寸先は闇 (issun saki wa yami, “unpredictable”).

the sixteenth night of the month under the lunar calendar, just after the full moon

Short for 十六夜の月 (izayoi no tsuki): the moon just past the full moon, the start of the waning moon

Nymphaea lotus, the white Egyptian lotus

(archaic, literary) to sleep with clothes overturned, as to meet their longed-for partner in a dream