1. To cause to be broken. "Your latest patch to the editor broke the paragraph commands."
2. (Of a program) To stop temporarily, so that it may debugged. The place where it stops is a "breakpoint".
3. To send an EIA-232 break (two character widths of line high) over a serial line.
4. [Unix] To strike whatever key currently causes the tty driver to send SIGINT to the current process. Normally, break, delete or control-C does this.
5. "break break" may be said to interrupt a conversation (this is an example of verb doubling). This usage comes from radio communications, which in turn probably came from landline telegraph/teleprinter usage, as badly abused in the Citizen's Band craze.
6. pipeline break.
7. break statement.