Which term refers to the back portion of the body or body part?

The term that refers to the back portion of the body or body part is "posterior." In anatomical terminology, "posterior" describes structures that are situated toward the back of the body when in standard anatomical position, which is standing upright with arms at the sides and palms facing forward. This positioning allows for a clear understanding of where different body parts are located in relation to one another.

"Anterior," on the other hand, refers to the front part of the body. "Medial" pertains to structures closer to the midline of the body, while "lateral" indicates structures that are farther away from the midline. Understanding these terms is crucial for accurately describing the location of various anatomical features, particularly in medical contexts, as it helps in the clear communication of observations and findings.