- A person who breaks into secure communications systems, especially telephone networks, and utilizes services which would otherwise be paid for. Also, to engage in such activity. For example, to send audio codes using a telephone line to obtain free calls.
- verb to hack into a telephone, telecommunications or computer system, in the patois of cyberpunks and net-heads. The term is a later back-formation from ‘phreaker’, the designation for the first hackers who interfered with the US telephone system for fun, in search of knowledge or for profit.