n.
In physics, the change of state of a substance from a solid to a gas without first becoming liquid.
One example is the vaporization of frozen carbon dioxide, or dry ice, at ordinary atmospheric pressure and temperature. The phenomenon occurs at pressures and temperatures (both relatively low) where solid and vapour phase s coexist in equilibrium. Preservation of food by freeze-drying involves sublimation of water from the food in a frozen state under vacuum.