1) An overly prominent jaw 
Prognathism is the positional relationship of the mandible and/or maxilla to the skeletal base where either of the jaws protrudes beyond a predetermined imaginary line in the coronal plane of the skull. In general dentistry, oral and maxillofacial surgery and orthodontics, this is assessed clinically or radiographically (cephalometrics). The word ...
• (n.) Projection of the jaws.
(prog´nә-thiz″әm) abnormal protrusion of one or both jaws, especially the lower jaw, the gnathic index being above 103. adj., prognath´ic, prog´nathous., adj.
Prog'na·thism noun (Anat.) Projection of the jaws. -- 
Type: Term Pronunciation: prog′nă-thizm Definitions: 1. The condition of being prognathic; abnormal forward projection of one or of both jaws beyond the established normal relationship with the cranial base; the mandibular condyles are in their normal rest relationship to the temporomandibular joints. Synonyms: progenia ...
Prognathism: An overly prominent jaw.
Condition characterized by an elongated lower jaw.
noun the condition of being prognathous; the condition of having a projecting jaw