Final answer:
The term for the encasement of an urn in the ground is a burial vault or tomb, which has been part of human burial practices for millennia, reflecting cultural, artistic, and symbolic significance in history, art, and literature.
Step-by-step explanation:
The term you are looking for, which defines a structure for the encasement of an urn in the ground, is commonly known as a burial vault or a tomb. This structure can range from a simple pit in the earth to a sophisticated stone or metal enclosure designed to protect the urn and its contents from the elements and any potential disturbances. Historically, burials have often included the placement of the body or ashes within coffins, sarcophagi, or urns. These containers were then placed in graves, sometimes marked by mounds or steles, to signify the resting place of the deceased. In many cultures, including the Romans and Etruscans, cremation was practiced, and the ashes of the deceased were stored in cinerary urns. These urns sometimes reflected the culture's artistic styles and funerary practices, as seen in the elaborately decorated containers that featured scenes or images of the deceased. The use of urns has not only practical significance but also symbolic importance in art and literature, where they are likened to containers holding stories, memories, or poetic meaning, as referenced by poets like John Donne and Thomas Gray.