What is a large mass of ice that moves slowly over land called?

A large mass of ice that moves slowly over land is called a glacier. Glaciers form from accumulated snow that compresses into ice over time, often found in mountainous regions or polar areas. The movement of glaciers is driven by gravity and the pressure of their immense weight, allowing them to flow and shape the landscape around them. This process can create unique landforms such as U-shaped valleys and fjords, showcasing the significant geological impact glaciers have on the earth's surface.

In contrast, an iceberg is a floating piece of freshwater ice that has broken off from a glacier or an ice shelf and drifts in the ocean. A snowfield refers to an area covered by snow and is often a temporary accumulation that does not necessarily have the same properties or movement characteristics of a glacier. Frost, while related to cold weather and ice formation, does not describe a large, moving mass, but rather a thin layer of ice crystals that forms on surfaces. Therefore, the correct term for a large, slow-moving ice mass is glacier.