辐射
fúshè · HSK 7
radiation
☢️ 辐 = vehicle-spoke + 射 = shoot → spokes shooting out = radiation
辐 originally meant the spokes of a wheel radiating from the hub; 射 means to shoot or emit. Together they describe energy shooting outward in all directions, like spokes from a center — hence radiation.
射 — body 身 + inch/hand 寸
Originally a pictograph of a hand drawing a bow with an arrow. The ancient form showed 弓 (bow) plus 矢 (arrow) or a hand. Over time it was reshaped into 身 (body) plus 寸 (hand/measure), and the meaning 'to shoot' was extended to 'emit' or 'project'.