The story
Borrowed from Mandarin 中山 (Zhōngshān) Wade–Giles romanization: Chung¹-shan¹. Chungshan is also a romanization of Cantonese 中山 (zung1 saan1), the name of the city in Guangdong, China, and it coincides with its Mandarin romanization of Chungshan.
Etymology from Wiktionary, CC BY-SA 4.0.