In music notation, Dal segno (dal ˈseɲɲo, ˌdæl ˈseɪnjoʊ or /ˈsɛɡnoʊ/) (often abbreviated D.S.) is used as a navigation marker. From Italian

Italian language

Italian is a Romance language spoken mainly in Europe: Italy, Switzerland, San Marino, Vatican City, by minorities in Malta, Monaco, Croatia, Slovenia, France, Libya, Eritrea, and Somalia, and by immigrant communities in the Americas and Australia...

 for "from the sign," D.S. appears in sheet music

Sheet music

Sheet music is a hand-written or printed form of music notation that uses modern musical symbols; like its analogs—books, pamphlets, etc.—the medium of sheet music typically is paper , although the access to musical notation in recent years includes also presentation on computer screens...

 and instructs a musician

Musician

A musician is an artist who plays a musical instrument. It may or may not be the person's profession. Musicians can be classified by their roles in performing music and writing music.Also....* A person who makes music a profession....

 to repeat a passage starting from the sign shown at right, sometimes called the "segno" in English.

Two common variants:

• D.S. al coda instructs the musician to repeat back to the sign, and when Al coda or To coda is reached jump to the coda
  Coda (music)
  Coda is a term used in music in a number of different senses, primarily to designate a passage that brings a piece to an end. Technically, it is an expanded cadence...
  
   symbol.
• D.S. al fine instructs the musician to repeat back to the sign, and end the piece at the measure marked fine.

Al segno indicates that the player should go to the sign.

In operas of the 18th century, da segno aria

Aria

An aria in music was originally any expressive melody, usually, but not always, performed by a singer. The term is now used almost exclusively to describe a self-contained piece for one voice usually with orchestral accompaniment...

s were a common alternative to da capo aria

Da capo aria

The da capo aria is a musical form, which was prevalent in the Baroque era. It is sung by a soloist with the accompaniment of instruments, often a small orchestra. The da capo aria is very common in the musical genres of opera and oratorio...

s which began with an opening ritornello

Ritornello

A ritornello is a recurring passage in Baroque music for orchestra or chorus. The first or final movement of a solo concerto or aria may be in "ritornello form", in which the ritornello is the opening theme, always played by tutti, which returns in whole or in part and in different keys throughout...

, which was then omitted in the repeat (the sign being placed after the ritornello).