What is the name of the process that converts a solid directly into gas?

The process of converting a solid directly into gas is called sublimation. This occurs when a substance transitions from a solid state to a gaseous state without first becoming liquid. A common example of sublimation is dry ice, which is solid carbon dioxide; it sublimates directly into carbon dioxide gas at room temperature.

In contrast, condensation refers to the process where gas changes into a liquid, while evaporation is the transformation of a liquid into a gas. Transpiration is a biological process where moisture is absorbed by plant roots and then released as vapor through leaves, which is not directly related to the solid-to-gas transformation. Thus, sublimation is distinct in its direct phase change from solid to gas.