Choir/ˈkwaɪər/ Definition 1 of 4Pro Tip 1/3Group Singing A choir involves collaboration, often performing in concerts or services. The choir rehearsed harmonies for the concert. Pro Tip 2/3Musical Variety Choirs vary by size and style, from gospel to barbershop. She joined a jazz choir for its vibrant style. Pro Tip 3/3Voice Parts Choirs usually have sections like soprano, alto, tenor, bass. He was placed in the tenor section of the choir.