The telephone (from the lang-el????, t?le, "far" and ????, ph?n?, "voice"), commonly referred to as a phone, is a telecommunications device that transmit (transmitter)s and receives sound, most commonly the human voice. Telephones are a point-to-point (point-to-point (telecommunications)) communication system whose most basic function is to allow two people separated by large distances to talk to one another. It is one of the most common household appliance (Small appliance)s in the developed world, and has long been considered indispensable to business, industry and government. The word "telephone" has been adapted to many languages and is widely recognized around the world.

The device uses a microphone in the handset to convert the sound waves to electrical signals (Signal (information theory)), which are sent through the telephone network (public switched telephone network) to the other phone, where they are converted back to sound waves by an earphone in the handset. The telephone network, consisting of a worldwide net of telephone lines, fiberoptic cables, microwave transmission, cellular networks, communications satellites, and undersea telephone cables (Undersea cable) connected by switching centers, allows any telephone in the world to communicate with any other. Each telephone line has an identifying number called its telephone number. In order to initiate a telephone call, a conversation with another telephone, the user enters the other telephones number into a numeric keypad on his phone. Graphic symbols used to designate telephone service or phone-related information in print, signage, and other media include unicode℡(U+ (Unicode)2121), unicode☎(U+ (Unicode)260E), unicode☏(U+ (Unicode)260F), and unicode✆(U+ (Unicode)2706).