What is a chorus in music?

A chorus can refer to a two different things in music. A chorus can refer to a large vocal ensemble or choir, consisting of several different sections according to voice type (bass, baritone, tenor, alto, and soprano, sometimes with subsets within different types i.e. alto 1 and 2 or soprano and mezzo soprano). It can also refer to a specific section within a composition. Before the advent of Rock and other current popular music, the chorus generally referred to the bulk of a popular song, with the verse being used as an introduction. In the heyday of Tin Pan Alley, the chorus would frequently follow a 32 measure form consisting of four eight measure sections. Currently, however, a chorus usually refers to a repeated section in a song -- often shorter than the verses with an intentionally catchy, recognizable melody -- that occurs between verses.