Definition
to deliver a concluding message at the conclusion of a letter, radio communication, or a television or radio broadcast
結束訊息（信件、廣播或電視節目）
At the end of the letter, she signed off her name formally, concluding the correspondence.
在信的結尾，她正式簽下自己的名字，結束了這封信。
The radio host always signs off with a saying at the end of the show.
廣播主持人總是在節目結束時用一句話來告別。
We signed off at the end of the recording, thanking the audience for listening.
我們在錄音結束時告別，感謝聽眾的收聽。