A bulb is a common term used to describe a light source, often used interchangeably with the term “lamp” in lighting and electrical contexts.
In professional lighting, audiovisual, and industrial applications, “bulb” is widely used by end users, but within technical environments the more precise term is “lamp.” Both terms describe the component that produces light within a fixture, whether through incandescent filaments, gas discharge, halogen processes, or modern LED technology. A bulb typically features a transparent or translucent enclosure—usually glass or polymer—that houses the light-generating element. Traditional incandescent bulbs used filaments, while halogen and gas discharge bulbs employed gases for efficiency. Today, LED bulbs rely on semiconductors for reduced power use and longer lifespans. While “bulb” is the popular term, “lamp” is preferred in commercial and industrial contexts to ensure precision in system design and specification.
Bulbs and lamps are subject to standards from IEC (International Electrotechnical Commission), ANSI (American National Standards Institute), and UL (Underwriters Laboratories). In the U.S., agencies such as the Department of Energy may regulate efficiency and safety requirements.
The term “bulb” originated in the late 19th century with the incandescent lamp, whose rounded glass envelope resembled a plant bulb. Over time, “lamp” became the industry’s technical term, though “bulb” remains the more common expression in everyday use.