‘海关’ (hǎi guān) literally means ‘sea official’, reflecting its historical origin as a government agency overseeing maritime trade and border control. Today, it refers to the national customs authority responsible for regulating the flow of goods, people, and vehicles across China’s borders — whether by sea, air, or land. Though the character 海 (‘sea’) suggests a maritime focus, the term is used broadly for all official customs checkpoints, including airports and land border crossings.

The word combines 海 (hǎi, ‘sea’) and 关 (guān, ‘pass’, ‘checkpoint’, or ‘barrier’), evoking the idea of a controlled entry point. In daily usage, ‘海关’ appears in contexts like airport arrivals, import/export procedures, duty-free shopping, and baggage inspection. It’s a formal institutional term — you’ll see it on signs, official documents, and news reports, but rarely in casual conversation unless discussing travel or shipping logistics.