Neck
The kanji and the word are exactly the same. That means they share meanings as well.
くび
You learned the reading for this word via the kanji, so you should be able to read this word just fine.
パソコンのしすぎで、首がいたいです。
I’ve been using my computer too much so my neck hurts.
首をねちがえました。
I cricked my neck in my sleep.
腺ペストって、首から胸が生えてくる病気のことですか？
Is the bubonic plague the illness that made people grow boobs on their necks?