Dictionary definition · light up
verb
- start to burn with a bright flame"The coal in the BBQ grill finally lit up"
- introduce light into"This lamp lightens the room a bit"
- become clear"The sky cleared after the storm"
- ignite"The sky lit up quickly above the raging volcano"
- begin to smoke"After the meal, some of the diners lit up"
Source: Open English WordNet (CC BY 4.0).