返始（意大利语：Da Capo，简称D.C.）是一种乐谱符号，指从头再奏，指示演奏乐章至记号后归回最初再次重复。功用上和重复相似，但返始可以更灵活使用。返始常见有Da Capo al fine和D.C. al Segno e poi la Coda（Da Capo al Coda），前者从头再奏后，演奏至「Fine」或「」记号时终结全曲；后者从头再奏后，然后演奏至记号，再跳至第二个记号完结。而拥有这种结构的歌剧则称为返始咏叹调，重复部分通常会加有装饰音。

Da capo, pronounced [da ˈkaːpo], is a musical term in Italian, meaning from the beginning (literally from the head). It is often abbreviated D.C. It is a composer or publisher's directive to repeat the previous part of music, often used to save space. In small pieces this might be the same thing as a repeat, but in larger works D.C. might occur after one or more repeats of small sections, indicating a return to the very beginning. The resulting structure of the piece is generally in ternary form. Sometimes the composer describes the part to be repeated, for example: Menuet da capo. In opera, where an aria of this structure is called a da capo aria, the repeated section is often adorned with grace notes.