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.
Old English cin, cinn chin (but in some compounds suggesting an older, broader sense of jawbone); a general Germanic word (cf. Old Saxon and Old High German kinni; Old Norse kinn; German Kinn chin; Gothic kinnus cheek), from PIE root *genu- chin, jawbone (cf.