The Chinese word **大洋** is a compound noun formed through a straightforward modifier-head structure, where the first character **大** (dà, meaning "big" or "great") acts as an adjective modifying the second character **洋** (yáng, meaning "ocean" or, by extension, "foreign" or "overseas"). Literally, it means "great ocean," historically referring to vast seas like the Pacific or Atlantic. However, its most common modern usage meaning "silver dollar" or "big coin" emerged through metonymy; during the late Qing and early Republican periods, large silver coins, often minted from foreign silver or used in major international trade across the oceans, became colloquially known by this term, linking the concept of the "large" currency to its "overseas" origin or influence.