Noun and の adjective
そうしき
もし誰かから電話があったら、葬式に出ていて三時に戻ると伝えてください。
If anyone calls, say I’m at a funeral and will be back at three o’clock.
A burial ceremony is a funeral.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.