The Chinese term for insulin, **胰岛素 (yídǎosù)**, is a semantically constructed loanword that precisely conveys its biological origin and function: the character **胰 (yí)** means "pancreas," **岛 (dǎo)** means "island" (referring specifically to the Islets of Langerhans within the pancreas), and **素 (sù)** denotes an essential biochemical substance. Thus, the compound directly translates to "pancreatic islet substance," forming a calque that accurately mirrors the anatomical source and chemical nature of the hormone, as opposed to being a phonetic borrowing.