Crown, Diadem, Bottle Cap
noun, の adjective
A king's cap is his crown. It's a hat only he can wear.
おうかん
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
彼は恋をして王冠を捨てたんだ。
He was in love and abandoned the crown.