What term describes the surface of one tooth that is touching another tooth?

The term that describes the surface of one tooth that is touching another tooth is "proximal." Proximal surfaces are the sides of a tooth that are adjacent to neighboring teeth, specifically referring to the areas that face each other in the dental arch. In the context of dental anatomy, understanding the proximal surfaces is essential for identifying how teeth maintain contact with one another and how they interact during chewing and other oral functions.

Other terms listed have specific meanings that do not describe this particular relationship. For instance, "cuspid" refers to a type of tooth, specifically canine teeth, while "facial" pertains to the surface of the tooth that faces the lips or cheeks. "Occlusal," on the other hand, describes the top surface of posterior teeth (molars and premolars) where biting occurs, rather than the contact area between adjacent teeth. Thus, "proximal" is the correct term for the surfaces of teeth that are in contact with one another.