Shi

市 shi simply means "city" or "market", and so it is part of many names of cities. It helps the "shi" sounds sort of like "city"
市 (shi) is an alternate form of the same character
中 zhong means China or center
中山市 Zhongshan-Shi means Zhongshan (Middle Mountain) City, which is in Guangdong province
上海市 Shanghai Shi is the city of Shanghai
广州市 Guangzhou Shi is the city of Guangzhou
天津市 Tianjin Shi is the city of Tianjin (near Beijing) 
台北市 Taipei Shi is Taipei City.
杰佛逊市 Jie-Fo-Xun Shi is Jefferson City (Missouri)
区 qu is "area, region, or district"
镇 zhen means "small town" 
市鎮 (shi zhen) is translated as just "town" 
心 xin means "heart, mind"
中心 zhong-xin is "center"
市鎮中心 (shi-zhen zhong-xin) is "town center"
政 zheng means "government" or "politics"
市政中心 (shi-zheng zhong-xin) means "civic center".  
市政中心 (旧金山) (shi-zheng zhong-xin Jiu-Jin-Shan) is the San Francisco Civic Hall