The concept of 重量 (zhòngliàng) is straightforward, but its practical application in China has a key cultural difference for Westerners: the units of measurement. While the international standard, the kilogram or 公斤 (gōngjīn), is the official unit of mass and used in most formal contexts (like shipping, industry, and official labeling), the traditional unit 斤 (jīn) is still alive and well in daily life. You will hear and use 斤 (jīn) constantly at wet markets, fruit stands, and local grocery stores.
This is comparable to how the United States uses the Imperial system (pounds, ounces) while the rest of the world uses the Metric system. However, in China, the two systems coexist much more closely in everyday commerce. A shopkeeper will almost always quote prices per jīn. For a beginner, mastering this conversion is one of the most practical skills for navigating daily life in China. Asking “这是公斤还是斤?” (Zhè shì gōngjīn háishì jīn? - Is this per kilogram or per jin?) can save a lot of confusion. Figuratively, a person or their words can have 重量, meaning they are influential and taken seriously. In this sense, it's very similar to the English phrase “to carry a lot of weight.”
重量 is a versatile noun used across various contexts, from casual to technical.