Topic summary
Vocalists

Extracted from the Wikipedia article Singing.
Popular and traditional music
In many modern pop musical groups, a lead singer performs the primary vocals or melody of a song, as opposed to a backing singer who sings backup vocals or the harmony of a song. Backing vocalists sing some, but usually, not all, parts of the song often singing only in a song's refrain or humming in the background. An exception is five-part gospela cappella music, where the lead is the highest of the five voices and sings a descant and not the melody. Some artists may sing both the lead and backing vocals on audio recordings by overlapping recorded vocal tracks.