There is a legend that in Ancient Rome, one of the members of the Senate each his speech, whatever topic it may be, ended with the words: "furthermore, I think Carthage must be destroyed". These words can be defined as a constant refrain of all his speeches.
French refrain translates as the chorus.
What is the refrain or chorus?
The so-called section of a musical work, which is completely without any changes is repeated several times. The refrain in songs called chorus. It is usually repeated after each verse. Unlike the introduction, the chorus usually has the same text, which expresses the General idea of the song. Often the chorus sung twice in a row, which gives it more weight.
And the term "refrain" is used, generally, in relation to the form of a Rondo, which has its origin from the couplet of the song.