Putty is a material used by glaziers, which is a type of tradesperson who specializes in the installation and repair of glass windows and doors. PUTTY is a malleable substance that is used to fill in gaps between the glass and the frame, providing a seal that prevents air and water from entering. It is also used to hold the glass in place and to provide a smooth finish. PUTTY is available in a variety of colors and can be applied with a PUTTY knife or other tools.