What does LED stand for? It stands for light-emitting diode, a small electronic part that gives off light when electric current passes through it. LEDs light up your phone screen, the bulbs in many homes, traffic signals and the little power dot on a TV.
Each word in the name tells you something. Light is what it makes. Emitting means sending out. A diode is a part that lets current flow in only one direction. Put together, an LED is a one-way electronic part that glows.
Quick facts
Stands for
Light-emitting diodeType
InitialismHow to say it
L E D, though some say "led"Plural
LEDsUsed in
Bulbs, screens, signs, car lights, remote controlsNot to be confused with
LCD, liquid crystal display
What does LED stand for? The three words
| Letter | Word | Meaning here |
|---|---|---|
| L | Light | Visible light, or in some LEDs infrared or ultraviolet |
| E | Emitting | Giving off |
| D | Diode | A two-lead part that passes current one way |
The hyphen in light-emitting joins two words that act together as one description. Some writers drop it, but the hyphenated form is the standard spelling.
How a light-emitting diode makes light
An LED is built from layers of semiconductor material. When current flows the right way, tiny charges meet at the boundary between the layers and release energy as light. The material decides the color. That is why an LED needs no filter to glow red, green or blue.
Because so little energy turns into heat, an LED bulb uses much less electricity than an old incandescent bulb for the same amount of light, and it usually lasts many times longer. Most white LED bulbs start with a blue chip and add a coating that turns part of that light into yellow, which our eyes see as white.
Where LEDs show up every day
- Home lighting: screw-in bulbs, strip lights under cabinets, porch lights.
- Screens: many TVs and monitors use LEDs to light the panel from behind.
- Cars: brake lights, turn signals, dashboard lights and headlights.
- Signals: traffic lights, exit signs and crosswalk timers.
- Remote controls: an infrared LED at the tip sends the signal you cannot see.
On a bulb box: "LED, 800 lumens, 9 watts, equal to 60 watt incandescent." The box is telling you the bulb gives about the same light as an old 60 watt bulb while drawing only 9 watts.
LED vs LCD and OLED
These three show up together on screen labels, and shoppers often blur them together.
| Term | Stands for | What it does |
|---|---|---|
| LED | Light-emitting diode | Makes light directly |
| LCD | Liquid crystal display | Controls light that shines from behind it |
| OLED | Organic light-emitting diode | Each pixel makes its own light |
A TV sold as an "LED TV" is usually an LCD screen with LEDs as the backlight. An OLED screen is different: its pixels glow on their own, so it needs no separate backlight.
Saying and writing LED
The standard way is letter by letter, "L E D," which makes it an initialism. Some people say it as the word "led," and you will hear that in shops, but the letter form is more common. Write it in capitals: LED, plural LEDs, no apostrophe.
Pair it with "an," since the name of the letter L starts with a vowel sound: "an LED bulb," "an LED strip." If you say it as "led," some writers use "a," but "an LED" is the usual written form. The acronym vs abbreviation guide explains the labels.
A short history of the LED
Scientists noticed that some materials glowed under current in the early 1900s. Practical visible LEDs arrived in the early 1960s, and the first ones glowed red. They were used in indicator lights and the red number displays of early calculators and digital watches. Green and yellow followed. Bright blue LEDs came much later, and they made white LED lighting possible.
For more short forms from electronics and computing, browse the tech acronyms section, including laser, another light source named with initials.
Questions people ask
What does LED mean on a light bulb?
It means the bulb makes light with light-emitting diodes instead of a heated wire. LED bulbs use less power and last longer.
Is LED an acronym?
It is usually an initialism, said L E D. Some people say it as one word, "led," and in that case it works like an acronym.
What is the LED acronym in a TV name?
In TV names, LED usually means the screen is an LCD panel lit from behind by LEDs. It is not the same as OLED.
Do you write an LED or a LED?
Most writers use "an LED" because it is read as "el E D," which starts with a vowel sound.