Incisors (from Latin incidere, "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Adult humans normally have eight incisors, two of each type. The types of incisor are:

  • maxillary central incisor (upper jaw, closest to the center of the lips)
  • maxillary lateral incisor (upper jaw, beside the maxillary central incisor)
  • mandibular central incisor (lower jaw, closest to the center of the lips)
  • mandibular lateral incisor (lower jaw, beside the mandibular central incisor)

Children with a full set of deciduous teeth (primary teeth) also have eight incisors, named the same way as in permanent teeth. Young children may have from zero to eight incisors depending on the stage of their tooth eruption and tooth development.

More Info: en.wikipedia.org