气球 (qì qiú) literally means 'air ball' — 气 (qì) means 'air' or 'gas', and 球 (qiú) means 'ball' or 'sphere'. Together, they refer to a lightweight, inflatable object typically made of rubber or thin plastic, filled with air or helium to make it float. It’s commonly used for celebrations like birthdays, festivals, and weddings, as well as in children’s play and educational demonstrations (e.g., static electricity or buoyancy).

In Chinese, 气球 is always a countable noun and usually appears with measure words like 个 (gè) or 只 (zhī). It can refer to both handheld balloons and larger decorative or promotional ones. Unlike English, where 'balloon' may occasionally imply metaphorical uses (e.g., 'ballooning debt'), 气球 is almost exclusively literal and concrete in everyday usage — you won’t hear it used figuratively without explicit context.