- Glass that is prestressed by heating and then rapidly cooled, a process that makes it two to four times stronger than ordinary glass. It shatters into pebbles instead of slivers.
- Glass which is subjected to sustained heating followed by cooling, each at suitable rates, to enhance its properties. Such glass flexes more, and resists impact, shock, thermal, and mechanical stresses. If broken, tempered glass fragments into comparatively harmless rounded pellets.
- noun toughened glass designed to shatter when struck and so prevent major injuries, used for such items as entrance doors and shower screens