Emit
verbBase emit · Past emitted · Past Participle emitted · Present Participle emitting · 3rd person emits
Definition
1. (verb) To send out light, sound, gas, heat, smell, or radiation from a source.
2. (verb) To produce or release something into the environment, especially as a by-product or side effect.
2. (verb) To produce or release something into the environment, especially as a by-product or side effect.
Context Alive
It's a quiet summer night and you're lying on the grass in your back garden, looking up. A small plane crosses the sky, and you notice the soft red light it emits blinking once every few seconds. Your dog suddenly perks up his ears at a sound only he can hear. You laugh, scratch behind his ears, and pull a blanket over your shoulders. The whole moment feels still and clean — just stars, a faint breeze, and a dog who refuses to lie down.
Meanings
2 meanings
1
To Send Out Light, Sound, or Gas (Verb)
Very Common
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This meaning is about a source releasing something — light, noise, smell, heat, smoke, gas — into the surrounding area. Imagine an old laptop that emits a soft humming noise whenever you turn it on, even after you've upgraded the fan twice. This is describing how something is sent out from the source, often without anyone doing anything specific to make it happen. You might say "the fridge emits a strange smell when the door is open", or someone could write "the lamp emits a warm yellow glow". Or picture a baby monitor in another room that quietly emits the sound of breathing while parents finally sit down for dinner. The word suggests that something is coming out continuously, naturally, or as part of how the source works.
✏️ Emit is a fairly formal word — common in science writing, news reports, and technical descriptions. In everyday speech, native speakers usually say give off instead: "the heater is giving off a weird smell." The noun form emission is everywhere too — "carbon emissions," "low-emission vehicle." Common sources you'll see emitting things: lights, sounds, smells, smoke, fumes, signals, radiation.
2
To Release Something into the Environment (Verb)
Common
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This meaning is about producing or releasing something — usually pollution, waste, or by-products — into the air, water, or surroundings. Imagine a factory that emits tons of carbon dioxide every year, no matter how many environmental rules are introduced. This is describing the kind of release we usually hear about in news reports about climate, health, or industry. You might read "cars emit greenhouse gases", or someone could say "the new technology emits less heat than older models". Or picture a study showing that certain materials in homes emit tiny chemicals over time — leading regulators to ban them. The word suggests release on a larger scale, often with environmental, scientific, or policy implications.
✏️ This use of emit is everywhere in climate and environmental writing. The most famous related word is emissions, which usually means greenhouse gases or pollution: "reduce emissions," "emission standards," "net-zero emissions." When discussing climate change, this is the verb you'll hear and see most often. Common targets: CO₂, methane, fumes, particles, radiation, pollutants.
Common Patterns
Basic Structures
emit + light/sound/heat/gas → the standard pattern with a thing being sent out
The old radio still emits a soft static sound when you turn it on.
emit + smell/fumes → describing a source releasing odour or gas
The kitchen vent emits a strong smell when something burns.
be emitted by + source → passive form, focusing on what is released
Carbon dioxide is emitted by power stations and vehicles.
Common Structures
emit + adverb (loudly, quietly, constantly) → describing how the emission happens
The fridge constantly emits a low buzzing noise.
emit + amount of + substance → quantifying what is released
The factory emits hundreds of tonnes of CO₂ every year.
fail to emit / stop emitting → describing the absence or end of emission
The bulb stopped emitting light after a few seconds.
Collocations
10 collocationsemit light
to give off light from a source
emit sound
to give off noise
emit heat
to give off warmth
emit smoke
to release smoke into the air
emit gas
to release gas into the environment
emit radiation
to release radioactive energy
emit a smell / odour
to give off a particular smell
emit fumes
to release strong-smelling gas, often harmful
emit greenhouse gases
to release gases that contribute to climate change
emit a signal
to send out an electronic or radio signal
Example Sentences
10 examples
1
The lamp emits a warm yellow light that fills the entire room.
The lamp gives off a warm, yellowish glow that brightens the whole room.
2
Cars emit greenhouse gases that contribute to climate change.
Vehicles release greenhouse gases that worsen climate change.
3
The old fridge emits a low humming sound at night.
The old refrigerator produces a quiet humming noise during the night.
4
Volcanoes emit huge amounts of ash and sulphur dioxide during eruptions.
Volcanoes release vast quantities of ash and sulphur dioxide when they erupt.
5
The new electric heater emits heat without producing any smell.
The new electric heater gives off warmth without releasing any odour.
6
Some animals emit sounds that humans cannot hear.
Certain animals produce sounds outside the range of human hearing.
7
The factory was fined for emitting too many pollutants into the river.
The factory was penalised for releasing excessive pollutants into the river.
8
Glow-in-the-dark stars emit light for several hours after the lamps go off.
Glow-in-the-dark stars give off light for hours after the lights are switched off.
9
The phone emits a small beep when the battery runs low.
The phone makes a short beep whenever the battery gets low.
10
Modern cars emit far less carbon dioxide than older models.
Modern vehicles release significantly less carbon dioxide compared to older ones.
Synonyms & Antonyms
6 items
Synonymsgive off
the most common everyday equivalent
release
broader, often used for liquids, gases, or substances
discharge
more formal, often used in technical/legal contexts
Antonymsabsorb
to take in instead of giving out
contain
to keep something inside
retain
to hold on to something rather than release it