What term describes the phenomenon of ice advancing and covering large areas of land?

The term that describes the phenomenon of ice advancing and covering large areas of land is glaciation. This process occurs over long geological time scales and involves the accumulation of snow and the transformation of that snow into ice, which can flow and expand into extensive sheets known as ice caps or glaciers. During glaciation, significant portions of the Earth's surface can be buried under thick layers of ice, affecting the landscape and climate.

In contrast, melting refers to the process where ice turns into water, which is the opposite of advancing ice. Condensation is the process by which water vapor turns into liquid water, commonly observed in the formation of clouds or dew, but does not involve ice advancing over land. Desiccation describes the process of drying out or evaporation, which is also unrelated to the concept of ice advancing. Therefore, glaciation is the correct term for the phenomenon of large areas of land being covered by ice.