four days from now; five days from now (regional)
Refers to the day four days after today in standard usage, but in some regions it means five days from now. Used both as a noun and adverbially.
五明後日は友達の誕生日だ。
Four days from now is my friend's birthday.
地域によっては、五明後日が五日後を指すこともある。
Depending on the region, 五明後日 can refer to five days from now.
Formed from 五 and 明後日 as a calendrical sequence name. Its reference varies regionally because traditional counting may include or exclude the present day.