Earthen means made of earth or soil. An earthen dam is built by packing dirt and clay together, not by pouring concrete or stacking stones. Ancient peoples built earthen mounds for burial sites and ceremonies by piling up soil into massive hills, some of which still stand today after thousands of years.

Earthen walls surround old fortresses in places like Morocco and China, where builders mixed dirt, clay, and straw to create surprisingly strong barriers. Adobe houses in the American Southwest have earthen walls that stay cool in summer and warm in winter.

Earthen can also describe things that look or feel like natural earth. An earthen floor might be hard-packed dirt instead of wood or tile. Potters sometimes refer to earthenware pottery, which is made from common clay and has that warm, earthy appearance.

Unlike “earthy,” which describes a smell or quality that reminds you of soil, earthen specifically means the material itself is earth, dirt, clay, or soil. When archaeologists discover earthen structures, they're finding buildings constructed from the ground itself.