Of Greek origin.
A masculine and feminine name too.
As a masculine name, Sandy is a diminutive of the name Alexander.
It is rarely used as a short for Santiago.
As a feminine name, it’s a diminutive of the name Alexandra or Sandra.
Male variants are: Sandey, Alex, Sacha, Alexandros, Olek, Xander, Alec, Alister, Al, etc.
Female variants are: Sandie, Ally, Sandra, Alexa, Alexandra, Alessandra, Lexie, Alejandra, etc.
Famous male bearers are Sandy Winton, Sandy Beales, Sandy Koufax, Sandy Lyle.
Famous female bearers are Sandy Denny, Sandy Lima, Sandy Mölling.