What term refers to the bottom or sole of the foot?

The term that refers to the bottom or sole of the foot is "plantar." This is an anatomical term used to describe the surface of the foot that makes contact with the ground when standing or walking. It is essential for understanding foot mechanics, as the plantar surface plays a significant role in weight-bearing and balance.

The other terms listed have different anatomical meanings. "Dorsal" refers to the upper surface of the foot (or the back of the hand), "palmar" pertains to the palm of the hand, and "volar" can refer to the sole of the foot or the palm, depending on the context. However, "plantar" is the specific term used exclusively for the underside of the foot, making it the correct choice in this context.