Incomplete repetition is a musical form featuring two large sections, the second being a partial or incomplete re-presentation or repetition of the first.

This form is used throughout the traditional Plains-Pueblo Native American music where the first section uses vocables and the second uses meaningful words. Typical formal schemes include ABC, BC, AABC, and ABC and each section uses a tile type melodic contour.

Source

• Nettl, Bruno (1956). Music in Primitive Culture. Harvard University Press