Break In

to enter a place or building by force, often in order to steal something

The thieves broke in through the back door and stole the TV.

The police had to break in to rescue the hostages.

to interrupt or intrude on someone or something

I'm sorry to break in, but I need to tell you something important.

The noise broke in on our conversation and we couldn't hear each other.

to train or wear in something new, such as shoes

I need to break in these new shoes before I wear them to the party.

The horse needed to be broken in before it could be ridden.