light up phrasal verb (see also light)

1. light something ↔ up to give light to a place or to shine light on something:
The flames lit up the sky.
The fountain is lit up at night.

2. to become bright with light or colour:
At night the harbour lights up.
As the screen lit up, he typed in his password.

3.
a) if someone’s face or eyes light up, they show pleasure, excitement etc
light up with
His eyes lit up with laughter.
Her face lit up with pleasure.
b) light something ↔ up to make someone’s face or eyes show pleasure or excitement:
Suddenly a smile lit up her face.
A mischievous gleam lit up her eyes.

4. informal to light a cigarette:
I watched Paul light up again.

[TahlilGaran] Dictionary of Contemporary English ▲

light up
light up (something/somewhere)
to add excitement to a place or thing.
She was one of those people who would light up a room.

Her personality doesn't exactly light up a television screen — in fact, she's painfully shy.

to look happy.
Grandma's eyes would light up when she started talking about her younger days.

[TahlilGaran] English Idioms Dictionary ▲

light up something
light up (something/somewhere)
to add excitement to a place or thing.
She was one of those people who would light up a room.

Her personality doesn't exactly light up a television screen — in fact, she's painfully shy.

to look happy.
Grandma's eyes would light up when she started talking about her younger days.

[TahlilGaran] English Idioms Dictionary ▲

light up
suddenly look pleased and happy
As soon as I told my cousin about our holiday plans his face lit up and he started smiling.

[TahlilGaran] English Idioms Dictionary ▲

light up
v. Suddenly to look pleased and happy.
Martha's face lit up when she saw her old friend.
Tom will really light up when he sees his new bike!

[TahlilGaran] English Idioms Dictionary ▲