An incandescent light bulb is a type of electrical light bulb that produces light with a wire filament heated to a high temperature by an electric current passing through it. The word "candid" comes from the Latin candidus, which means "shining white" or "glowing." This likely refers to the white-hot glow of the filament of an incandescent light bulb when it is lit. Over time, the meaning of the word has shifted from referring to the physical appearance of the light bulb to referring to a person's honesty and openness in speaking or expressing their opinions.