Noun and Prefix
はん
わたしはこのえいがを三かい半みました。
I’ve watched this movie three and a half times.
JLPTまであと一ヵ月半しかありません。
There is only a month and a half left until the JLPT.
かの女は半じゅくたまごのようにかわいいね。
She is as cute as a half-cooked egg.
The kanji and the word are exactly the same. That means they share meanings as well.
Since this word is made up of a single kanji, it's supposed to use the kun'yomi reading. But, there is no useful kun'yomi reading for this kanji, so even the single kanji vocab word version uses the on'yomi reading, which you've already learned!