Da capo (Italian "from the head") is a musical term that instructs the performer to return to the beginning of the movement and repeat until a specified ending (usually marked Fine). It is often abbreviated "D.C. al fine." When this is observed, the movement acquires a ternary, or ABA form.
Similarly, a da capo aria is a vocal piece common in Baroque opera which follows this form. Usually, during the repeat of the opening section, the singer was expected to improvise and embellish the melody.