Shout chorus

A refrain (from Vulgar Latin refringere, "to repeat", and later from Old French refraindre) is the line or lines that are repeated in music or in verse; the "chorus" of a song. Poetic fixed forms that feature refrains include the villanelle, the virelay, and the sestina.

The use of refrains is particularly associated with where the verse-chorus-verse song structure typically places a refrain in almost every song. The refrain or chorus often sharply contrasts the verse melodically, rhythmically, and harmonically, and assumes a higher level of dynamics and activity, often with added instrumentation. Chorus form, or strophic form, is a sectional and/or additive way of structuring a piece of music based on the repetition of one formal section or block played repeatedly.

In music, a refrain has two parts: the lyrics of the song, and the melody. Sometimes refrains vary their words slightly when repeated; recognisability is given to the refrain by the fact that it is always sung to the same tune, and the rhymes, if present, are preserved despite the variations of the words. Such a refrain is featured in "The Star-Spangled Banner," which contains a refrain which is introduced by a different phrase in each verse, but which always ends:

A similar refrain is found in the "Battle Hymn of the Republic," which affirms in successive verses that "Our God," or "His Truth," is "marching on."

...
Wikipedia