Used to label an unusually large number of occurrances of a disease or condition in one place. An autism cluster would be an unusually large number of cases of autism in (perhaps) a single locality. Clusters constitute evidence in the search for causes of diseases and conditions.
Top definition. jawn. a word used by Philly cats to describe anything and everything. NY cats interject with the word joint but it doesn't convey the same feelings.
The mandible, or lower jaw, is the bone that forms the lower part of the skull, and along with the maxilla (upper jaw), forms the mouth structure. Movement of the lower jaw opens and closes the mouth and also allows for the chewing of food. The lower set of teeth in the mouth is rooted in the lower jaw.