This word is a case of grammatical evolution. Coming from the Latin word meaning 'To check with a bridle', the original meaning has been distorted somewhat by its move into other languages. In modern language one would say 'rein in', for the exact same meaning. Why the term is used to refer to poetry and music at all is debatable, because the etymology doesn't support it. The expression now means something entirely different.
Examples of Refrain:
|Common usage: To withhold an action, to not do something, or cease doing.|
Poetry and music: A repeated phrase within a poem or piece of music.