The horizontal projection of the maxillary incisors beyond the mandibular incisors when the jaws are in centric (habitual) occlusion.
A space which separates the top incisors from the bottom incisors when the jaws are closed.
The jutting out of the upper incisor teeth in front of the lower ones.
Horizontal overlap of the teeth, especially between the lingual surface of the maxillary incisors and the labial surfaces of the mandibular incisors.