A horse was released from the stable.
I worked hard and was finally released from my debts.
I thought that I was finally free of having to care for my children but then my 53-year-old wife got pregnant again.
This word consists of kanji with hiragana attached. Because the hiragana ends with an う sound, you know this word is a verb. The kanji itself means release and the verb vocab version means to be released. You can differentiate this one from 放す (to release) by thinking that it's pretty rare (れる) for you to be released by your arch nemesis. He just let you go, strangely. How rare.
The reading comes from 放す. As long as you know that word you can apply that reading over here as well.