Overjet refers to the extent of horizontal (anterior-posterior) overlap of the maxillary central incisors over the mandibular central incisors. In class II (division I) malocclusion the overjet is increased as the maxillary central incisors are protruded. ... Found on http://en.wikipedia.org/wiki/Overjet
(o´vәr-jet″) extension of the incisal or buccal cusp ridges of the upper teeth horizontally (labially or buccally) beyond the ridges of the teeth in the lower jaw when the jaws are closed normally. Found on http://www.encyclo.co.uk/local/21001