扩建 (kuò jiàn) is a verb meaning 'to expand (a building or structure)' — typically by adding new space, floors, wings, or facilities to an existing facility. The first character 扩 (kuò) means 'to expand' or 'to enlarge', while the second character 建 (jiàn) means 'to build' or 'to construct'. Together, they convey the idea of enlarging something that already exists through construction, rather than building from scratch. It’s commonly used for schools, hospitals, factories, airports, and residential complexes.

This word implies intentional, planned physical growth of infrastructure and is often found in official announcements, news reports, urban planning documents, and real estate contexts. Unlike general terms like 'build' or 'construct', 扩建 specifically requires an existing structure as its object — you cannot 扩建 something that doesn’t yet exist. It’s a formal, neutral-term verb, appropriate in both written and spoken standard Chinese, though rarely used in casual daily conversation.