Graduation Ceremony, Graduation
noun
You know that 卒業 is graduation so what about when you add ceremony to it? That makes it a graduation ceremony.
そつぎょうしき
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. It will help if you know how to read 卒業 already as a word, too.
明日は私の卒業式です。
Tomorrow is my graduation ceremony.
あ、これ、卒業式の後の写真だね。なつかしい！
Ah, this is a photo from after the graduation ceremony, right? How nostalgic!
はあ？卒業式にビヨンセが来て歌を歌ってくれた？まさか！冗談でしょう？
Huh? Did you say that Beyoncé came to the graduation and sang for you guys? No way! You must be joking!