A light-emitting diode (LED) is an electronic device that emits light when an electric current is passed through it. There are a number of synonyms for the term "LED," including solid-state lighting, semiconductor lighting, and digital lighting. In addition, LEDs can be referred to by their color temperature, such as warm white LED or cool white LED. Other designations for LEDs may be based on their shape, such as LED strips, LED bulbs, and LED arrays. Overall, the popularity of LEDs has grown rapidly in recent years due to their energy efficiency, long lifespan, and ability to produce a range of colors and brightness levels.