Department, Station, Office
Noun and Suffix
きょく
ゆうびん局とびょういんもあります。
There is a post office and a hospital, too.
あのテレビ局、のっとっちゃおうぜ！
Let's take over that TV station!
彼は、マクドナルドのドライブスルーで待たされすぎたからといって、アメリカ連邦捜査局に電話をかけようとした。
He tried calling the Federal Bureau of Investigation because he had to wait too long in the drive-thru at McDonald's.
The kanji and the word are exactly the same. That means they share meanings as well.
The kanji and the vocab are exactly the same, even the reading. This one uses the on'yomi probably because it's often attached to other words (specifying a bureau, for example), so that's why it follows jukugo conventions despite being all alone.