What is the act of placing a deceased human body in the ground called?

The act of placing a deceased human body in the ground is referred to as interment. This term specifically pertains to the process of burying a body in a grave or tomb and is often used in legal and formal contexts regarding funerals and the treatment of the deceased. Interment is a key concept in discussions of burial practices and is distinguished from other related terms, such as burial which, while sometimes used interchangeably, generally refers to the broader practice of placing the body in the ground or in a burial site.

Inurnment refers to placing ashes in an urn, which is relevant in the context of cremation, and retirement does not relate to any practices associated with handling the deceased. Thus, interment is the most accurate term that specifically denotes the act of burial in the ground, aligning perfectly with the context of the question.