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 jaw is a part of the buccal cavity that is critical to the chewing of food. It is made up of a fixed upper jawbone, known as the maxala, and a mobile lower jawbone, known as the mandible. Together these two parts move back and forth to facilitate the tearing and chewing of food by the teeth.