Signal

Signal, signals, signaling or signalling may refer to:

Science

C signal handling, a way for handling signals received by programs during their execution
SIGNAL (programming language), a synchronous programming language
Signal (software), a free and open-source encrypted voice calling and instant messaging application developed by Open Whisper Systems
Unix signal, a limited form of inter-process communication used in Unix, Unix-like, and other POSIX-compliant operating systems

Beacon
Distress signal
International Code of Signals
International maritime signal flags, using the International Code of Signals
Maritime flag signalling, generally flaghoist signalling, by which ships communicate with each other
Morse code
Naval flag signalling, covers various forms of flag signalling, such as semaphore or flaghoist
Recognition signal in human, technical or biological communications
Signal (electrical engineering), a function that conveys information about the behavior or attributes of some phenomenon
Signal strength
Signals (military), military communications
Signaling (telecommunications), a part of some communication protocols
Smoke signal
Telegraphic signal, in telegraphy
Busy signal, in telephony

Signal Mountain (Wyoming)
Signal, a New York Yiddish-language literary monthly published from 1933 to 1936 by the Communist Party USA
Signal (magazine), a Wehrmacht propaganda magazine which was published in occupied Europe during World War II
SIGNAL Magazine, publication of the Armed Forces Communications and Electronics Association
Signal (toothpaste)
Signal 1 and Signal 2 radio stations
Signaal (now Thales Nederland), a Dutch defense company
Signal Systems, a telecommunications company of the McLean Group of Companies
Signal – The Southeast Electronic Music Festival, an annual music festival held in the United States
Signal (novel), a 2009 children's novel about a boy who helps a girl from another planet signal her parents
USS Signal, the name of more than one US Navy ship