1. To force entry into a physical structure, often a building. They called the police as soon as they heard someone break into their house. I had to break into the house—I didn't have my key, and no one else was home!

2. To forcibly access something (often a computer system) that one is prohibited from. Someone must be breaking into our system—how else would the media know such classified information?

3. To interrupt something. I'm sorry to break into your conversation, but I have some information that might help.

4. To establish a career in a particular industry or profession. She may be a successful actor now, but it took her years to break into the industry.

5. To suddenly perform a particular action. My friends and I love theater, so you can always count on someone just breaking into song. My mother was fine this morning, but she broke into tears at the funeral.

6. To split into smaller pieces. In this usage, a noun or pronoun can be used between "break" and "into." I know the project is daunting, but let's break it into manageable parts that each of us can work on. Because there was only one cookie left, I broke it into pieces so each of the kids could have some. The vase hit the floor and broke into pieces.