What word describes the process of changing directly from a gas to a solid?

The term that accurately describes the process of changing directly from a gas to a solid is deposition. This process occurs when gas particles lose energy and transition into a solid state without first becoming a liquid. An example of deposition can be observed in frost formation, where water vapor in the air turns directly into ice on cold surfaces.

In contrast, condensation refers to the transition from gas to liquid, which involves the gas molecules coming together to form a liquid due to a decrease in temperature or pressure. Fusion pertains to the process of a solid becoming a liquid, commonly known as melting. Vaporization is the process where a substance transitions from a liquid to a gas, either through evaporation or boiling. Thus, deposition is specifically the term that denotes the direct transition from gas to solid.