‘吨位’ (dūnwèi) literally combines ‘吨’ (dūn), meaning ‘ton’, and ‘位’ (wèi), meaning ‘position’ or ‘capacity’. In maritime and logistics contexts, it refers to a ship’s tonnage—the measure of its internal volume or cargo-carrying capacity, expressed in tons. It is not about weight alone but reflects the vessel’s size and functional scale, often used for classification, regulation, and port fees.

This term appears frequently in shipping documents, naval reports, port authority announcements, and news about maritime trade or shipbuilding. While occasionally extended metaphorically (e.g., ‘data tonnage’), its core usage remains technical and formal, tied to vessels and transport infrastructure. Learners should note that ‘吨位’ is always uncountable and does not take measure words like ‘个’; it functions as a standalone noun denoting a standardized metric.