noun, noun or participle which takes 'suru', intransitive verb
letter left behind; farewell note
A note or letter left for someone when the writer departs, often placed in a visible spot. Can be used as a noun or with する to describe the act of leaving such a letter.
彼は机の上に置き手紙を残して家を出た。
He left a note on the desk and left the house.
急用で先
I have to leave early for an urgent matter, so I'll leave a note.