Prognathic

Part of speech: adjective

Definitions

1. Having a lower jaw or jaws that protrude forward beyond the upper face, a feature often noted in anatomy and physical anthropology
2. Describing a face or skull whose jaws jut outward past the line of the forehead and nose
3. Characterized by a forward-projecting jaw, a trait studied in human and primate skulls alike

Etymology: "Prognathic" is built from two Greek elements: "pro-", meaning "forward", and "gnathos", meaning "jaw". The second part survives in English in "gnathic" and in technical terms such as "orthognathic", where the jaw is set straight, so a prognathic jaw is one that projects forward beyond the face above it. The word is a modern scientific formation, assembled from classical parts rather than inherited from ancient Greek. Ancient speakers had no use for a term describing a jaw's angle in anatomical or anthropological comparison, so the word belongs to the vocabulary of later science, when naturalists and physicians needed precise labels for skull shapes. Its usefulness lies in the fact that the same Greek root gives English a whole family of jaw terms, which lets specialists describe the position of the jaw with a single word instead of a sentence.

Synonyms: prognathous

Antonyms: orthognathic