intercom

This term is a portmanteau of internal communication. It describes a specific type of electronic voice system used for short-distance communication within a single premises, such as an office, a home, or a secure facility. It is distinct from a telephone system in that it typically operates on a closed circuit and often allows for one-way or half-duplex communication.

In modern contexts, the word is frequently associated with security checkpoints, such as the panels found at apartment building entrances. While the technology has evolved into digital and IP-based systems, the term remains the standard designation for any integrated speaker-microphone system used for internal building coordination.