The word "霓虹灯" is formed by combining the characters "霓" (meaning a secondary rainbow or halo), "虹" (meaning rainbow), and "灯" (meaning lamp or light). The compound "霓虹" phonetically approximates the English word "neon" and conceptually suggests colorful light, while "灯" denotes the object as a lighting device, together creating the term for "neon light".