Definition: A liquid boils over when you boil it so hard that it rises and flows over the edge of the suacepan or other container.
(this phrasal verb has more than one meaning)
E.g.1: What’s that terrible smell? Sorry, I was heating some milk but I didn’t watch it and it boiled over.
E.g.2: Someone had put too much water in the kettle so it boiled over and made everything wet.
This phrasal verb can’t be separated.