A chorale is a piece of music that praises God, usually sung in church by a lot of people together. The classic ones are the old German hymn-tunes — a sturdy melody the whole congregation can sing, later often dressed in richer harmony (Bach wrote a great many). In English, chorale points at that kind of hymn, not at any choir song at all. It is a noun, a little specialised: you meet it in church, in music class, and on concert programmes, not in everyday chat.