From MusiCAD

A Segno (Italian for sign) usually shown as segno is used as a return-marker within dal-segno piece.

D.S., short for Dal Segno usually written near the end of a composition denotes: repeat from the sign.

Other symbols are used as well like a paragraph sign.

dal segno example

The segno and coda position, color, size etc. may be adapted with the dialog [Options|Music]