電灯
でんとう · dentou · JLPT N4 · noun
light bulb
💡 電灯 = electricity (電) + lamp (灯)
電 (den) is the electricity character found in 電話 (telephone) and 電車 (train). 灯 (tou) means lamp or light, as in 灯台 (lighthouse). Sound hook: den-tou — the DEN gets its light from a lamp that TOE-taps on.
灯 — fire radical 火 + ding 丁 (phonetic)
灯 is a semantic-phonetic compound: 火 'fire' gives the meaning (lamps once burned oil or flame), while 丁 hints at the sound. It is the simplified form of the traditional 燈, which used 登 as the phonetic. Today it means 'lamp' or 'light'.