The Chinese word 暖气 (nuǎnqì) is a compound noun formed by combining the character 暖 (nuǎn), meaning "warm", with 气 (qì), meaning "air" or "steam". Literally, it translates to "warm air", but its modern meaning is "heating" or "central heating system", specifically referring to the radiator-based heating common in Northern China. This semantic shift occurred through metonymy, where the source (the warm air or steam produced) came to represent the entire system that generates it. Therefore, the term elegantly captures both the fundamental principle (warming the air) and the functional appliance or infrastructure itself.