What part of the tooth is located closest to the tongue?

The part of the tooth located closest to the tongue is referred to as the lingual surface. This term is derived from the Latin word "lingua," which means tongue. The lingual surface is the inner side of the tooth that faces the tongue and is significant in dental anatomy because it is involved in various functions such as speech and the manipulation of food during chewing.

In contrast, the buccal surface refers to the outer side of the teeth that faces the cheeks, while the cervical area pertains to the region of the tooth near the gum line. The occlusal surface is the top part of the tooth that comes into contact with opposite teeth during biting and chewing. Thus, the lingual surface being closest to the tongue defines its unique position among the different surfaces of a tooth.