JAMA, in this meaning, is not a place and not a person’s name. It is the short name of a famous American medical journal: the Journal of the American Medical Association. Doctors and researchers all over the world read it for new studies, new drugs, and new ways of treating people. In speech you say the four letters, J-A-M-A, not “jama” as one word. It is a journal — a serious magazine of research papers — not the medical association itself; the association behind it is the AMA. When a doctor in Taiwan says “I read it in JAMA,” this is the journal they mean.

JAMA（《美國醫學會期刊》；台灣醫界都直接唸這四個字母）