Noun and の adjective
れい
うちの母親は、僕が零点を取ると、キーッと癇癪を起こします。
My mom really loses her temper if I get zero marks on my exams.
The kanji and the word are exactly the same. That means they share meanings as well.
The reading is the same as the one you learned with the kanji. That's 零 extra things for you to learn.