In a Nutshell: The most common job of 栋 (dòng) is to count buildings. In English, we might just say “one building,” but in Chinese, you need a classifier, and 栋 is the perfect one: “一栋楼 (yí dòng lóu)”. Its origin comes from the noun for a roof beam—the most critical piece of a traditional house. Because of this, 栋 also has a powerful metaphorical meaning. To call someone a 栋梁 (dòngliáng), or “beam,” is to say they are an indispensable pillar of support for their family, company, or country.