荧光
yíng guāng · HSK 7
fluorescence
💡 荧光 = 荧 (glimmer/glow) + 光 (light) = glowing light, i.e. fluorescence
荧 carries the sense of a faint flickering glow (it also names fireflies, 荧火虫), and 光 is plain light. Stick them together and you get the cold glow of a fluorescent tube or a highlighter marker.
光 — fire 火 (top) + person 儿 (bottom)
Originally a pictograph of a person with fire above their head, depicting a torchbearer or the radiance from a flame. The character evolved to mean 'light' or 'brightness' in general, and by extension 'glory' and 'to shine.' The modern top component is a stylized form of 火 (fire).