In italian, segno means sign, and in music theory its symbol is:
Italian, Dal segno (D.S.) means from the sign, and in music theory it is like a repeat sign: You had to repeat the section between two signs, like this:
The second sign can be replace by D.S or by Dal Segno, but it is the same:
Dal segno al fine
In italian, Dal segno al fine means from the sign to end, so after you go back to the sign you have to stop at the Fine indication, like this:
Ancient notation of Dal Segno
In some ancient music score, you will find this:
But it is the same, the sign was different.