Noun
かじ
火事があった場所は、アパートの五かいです。
The fire was on the fifth floor of the apartment.
何か臭うんだけど。もしかして、火事じゃない？
I smell something strange! Maybe a fire?
昨日、家が火事になる夢を見たんです。
Yesterday I had a dream that my house caught on fire.
Fire is a thing that makes more fire. Basically fire is fire.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.