To emit means to send out or give off something, usually energy, light, sound, smell, or particles. A flashlight emits light. A radio emits sound waves. A campfire emits heat and smoke. Your body emits warmth.

The word suggests something flowing outward from a source. Scientists talk about how the sun emits radiation, how volcanoes emit gases, or how certain materials emit particles as they decay. A smoke detector works by emitting an invisible beam of light and checking whether smoke blocks it.

You'll often see emit used in science and technology contexts, but the word applies to everyday situations too. A factory emits pollution into the air. A phone emits a beeping sound when you get a text. Even a flower emits fragrance.

The noun form is emission. When people talk about reducing carbon emissions, they mean decreasing the amount of carbon dioxide that cars, factories, and power plants emit into the atmosphere. An emission is simply whatever gets emitted: light emissions from a screen, sound emissions from speakers, or heat emissions from an engine.