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.
Definition. A nonagon is a nine-sided polygon. You may recall that a polygon is a many-sided shape. We use the suffix-gon to indicate the number of sides of a polygon.