What is the process where a substance changes from a gas directly to a solid?

The process where a substance changes directly from a gas to a solid without passing through the liquid phase is called "deposition." During deposition, the gas molecules or particles lose energy and come together to form a solid. This is the opposite of sublimation, where a substance changes directly from a solid to a gas without going through the liquid phase. Both deposition and sublimation are phase transitions that involve the conversion of matter between the gas and solid phases.