'辐射' (fú shè) literally combines 辐 (fú), meaning 'spoke of a wheel' — suggesting rays emanating outward like spokes — and 射 (shè), meaning 'to shoot' or 'to emit'. Together, they form the noun 'radiation': energy emitted as particles or electromagnetic waves. It is used broadly in physics, medicine, environmental science, and daily life — for example, sunlight contains visible and ultraviolet radiation, while X-ray machines use ionizing radiation for diagnostics.

The term carries neutral scientific weight but often appears with modifiers indicating type or safety: '电磁辐射' (electromagnetic radiation), '核辐射' (nuclear radiation), or '低辐射' (low-radiation). In Chinese media and health discussions, it frequently appears in warnings (e.g., about mobile phone or microwave oven emissions) or reassurances (e.g., '符合安全辐射标准'). Unlike English, '辐射' is almost never used as a verb in modern standard Mandarin — it remains strictly nominal.