Belong To
Noun, する verb, and の adjective
しょぞく
所属部署に病欠のための診断書を提出しておいた方がいいよ。
You should turn in doctor’s notes for sick days to your own department.
A place where something belongs is where it is attached. It's where it's attached to. It belong(s) to that place.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.