The Chinese term 反应堆 (fǎnyìngduī), meaning "nuclear reactor," is a logical compound word formed by combining 反应 (fǎnyìng), meaning "reaction" (specifically referring to the nuclear chain reaction), with 堆 (duī), which literally means "pile" or "heap." This construction directly reflects the term's scientific origin, as the first artificial nuclear reactor was literally a "pile" of graphite and uranium blocks wherein the fission "reaction" took place. Thus, the term is a semantically transparent, descriptive compound that accurately denotes the core function and historical structure of the device.