light up
2 meanings
suddenly look happy and excited (face or eyes)
What does "light up" mean in this sense?
Examples
- Her face lit up when she saw all her friends waiting at the door.
- His eyes always light up at the mention of football.
- She lit up the moment she heard she'd got the job.
How to use it
The most common pattern, where 'face' or 'eyes' is the grammatical subject and there is no object.
Her face lit up the moment she heard she'd been accepted.
The whole person can be the subject, standing in for their expression — a common shorthand in natural speech and narrative writing.
He lit up completely when his old university friend walked through the door.
Use a 'when' clause to show what triggered the emotional reaction.
Her eyes lit up when she spotted her name on the list.
Use 'at' to introduce the trigger as a noun phrase, especially for mentions or sights.
His face lit up at the mention of his favourite band.
Adverbs like 'immediately', 'suddenly', or 'visibly' are often added to stress how instant and spontaneous the reaction was.
Her eyes immediately lit up when she saw the surprise waiting for her.
Common Collocations
Common Mistakes
In this emotional sense, 'light up' is intransitive — the face or eyes are the subject, not the object. Saying 'the news lit up her face' shifts to the illumination sense and sounds unnatural here.
When a light source (like a lamp or fireworks) makes a place brighter, a different sense of 'light up' is in play. The emotional sense always needs a face, eyes, or person as the subject — never a light source or location.
Learners sometimes leave out adverbs like 'immediately' or 'suddenly', making the sentence sound less vivid. These adverbs fit naturally just before or after the verb to emphasise how spontaneous the reaction was.
Usage
This phrasal verb is neutral and works in both spoken and written English. It almost always appears in the simple past when telling a story ('her face lit up'), and the subject is nearly always 'face', 'eyes', or the person themselves.
make something bright with light
Sense 2: What does "light (sth) up" mean?
Examples
- Fireworks lit up the night sky on New Year's Eve.
- The engineers lit the entire stadium up for the opening ceremony.
- The old town was lit up by hundreds of lanterns during the festival.
How to use it
The most common pattern, where a light source makes a place or object brighter.
Hundreds of lanterns lit up the old harbour.
When the object is a short noun phrase, it can go between 'light' and 'up'.
The spotlights lit the stage up beautifully during the performance.
When the object is a pronoun, it must go between 'light' and 'up' — never after 'up'.
The screen was completely dark, but a notification lit it up.
The passive form is common when describing how a place or object appears when illuminated.
The city centre was lit up by thousands of fairy lights during the festival.
Used when a place or object becomes bright, without mentioning the specific cause.
The whole street lit up as the parade passed by.
Common Collocations
Common Mistakes
The correct past tense is 'lit up', not 'lighted up'. 'Lighted up' sounds unnatural and old-fashioned to most native speakers.
When the object is a pronoun like 'it' or 'them', it must go between 'light' and 'up'. Placing it after 'up' is ungrammatical.
'Light up' can also mean to start smoking a cigarette, so context matters. The illuminate sense takes a place or object as its target (e.g. 'the sky', 'the room'); the smoking sense is usually used alone or with 'a cigarette'.
Usage
This phrasal verb is neutral in register and works in both spoken and written English. Remember that when the object is a pronoun, separation is required: say 'it lit the room up' or 'it lit it up', never 'it lit up it'.
Frequently Asked Questions
Does 'light up' in this sense always need 'face' or 'eyes' as the subject?
Almost always, yes — 'face' and 'eyes' are by far the most natural subjects. However, the whole person can also be the subject as a shorthand, for example 'she lit up when she saw him'. What you can't do is use an object, place, or light source as the subject in this emotional sense.
Can I use 'light up' in the present tense to describe a habit or general truth?
Yes, the simple present works well for habits or characteristic reactions, for example 'his eyes always light up when someone mentions travel'. The simple past is most common in storytelling, but the present tense is perfectly natural when you're describing something that happens regularly.
Does 'light up' always describe a positive emotion?
Yes, in this sense it always signals a positive reaction — typically joy, excitement, or recognition. It would sound odd to use it for negative emotions like anger or sadness. If you want to describe a sudden negative change in expression, a different phrase would be more appropriate.
Is 'light up' in this sense the same as 'brighten up'?
'Brighten up' is very close in meaning, but there's a subtle difference: 'light up' suggests a more sudden, dramatic, and visible change in expression, while 'brighten up' can feel slightly more gradual or gentle. Both are natural, but 'light up' tends to be more vivid and impactful.
Can I use 'light up' in the future continuous, like 'her face will be lighting up'?
This would sound awkward because 'light up' in this sense describes a spontaneous, involuntary reaction rather than a planned or ongoing action. It's best to stick to simple tenses — the simple past is most common, and the simple present works well for habits or predictions.
Can 'light up' be used in the passive?
Yes, the passive is very natural with this sense. You will often see it in descriptions of decorated places or events, for example: 'The bridge was lit up in blue for the celebration.' It is a common structure in both spoken and written English.
Does 'light up' always need an object?
No. You can use it without an object when the focus is on the place or thing that becomes bright. For example, 'The dashboard lit up as soon as I started the car.' In this pattern, the place or thing is the subject, not the object.
Is 'her smile lit up the room' about illuminating or something else?
This is a figurative extension of the illuminate sense. The subject (a smile, someone's presence) is acting on a place (the room), making it feel brighter or warmer. It naturally belongs with this meaning of 'light up', not the separate sense about a face or eyes showing happiness.
What kinds of things are typically the subject when using 'light up'?
Common subjects are light sources and bright objects: fireworks, spotlights, candles, neon signs, fairy lights, floodlights, and screens. Something non-physical, like a smile, can also be the subject in figurative uses. A person's face or eyes as the subject, however, signals a different sense of 'light up'.
Can I separate 'light up' with a long noun phrase?
It is better not to. With short noun phrases like 'the sky' or 'the stage', separation works well: 'they lit the stage up'. But with long phrases, it sounds more natural to keep the phrasal verb together: 'the lights lit up the entire northern side of the building' is much smoother than separating it.
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