Zero
noun, の adjective
The kanji and the word are exactly the same. That means they share meanings as well.
れい
The reading is the same as the one you learned with the kanji. That's 零 extra things for you to learn.
母は、僕が零点を取ったことにショックを受けて寝込んでしまった。
My mother was so shocked that I got zero points on my test that she's bedridden.