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.
Jawa. Jawas are meter-tall humanoids completely hidden behind rough, hand-woven robes. Their faces are concealed within the dark folds of a cowl, from which peer their sickly glowing yellow eyes. They comb the deserts of Tatooine in search of discarded scrap and wayward mechanicals.