# Signal (disambiguation)

A signal is any variation of a medium that conveys information.
Signal or signaling may refer to:

## Science and technology

* Analog signal
* Audio signal
* Digital signal
** Digital signal (signal processing)
* Cell signaling, in biology
* Signalling (economics), in economics theory
* Signal processing, subfield of electrical engineering
* Signalling theory, in evolutionary biology
* Time signal

### Computing

* SIGNAL (programming language), a synchronous programming language
* Signal (software), an end-to-end encrypted voice calling, video calling and instant messaging application
** Signal Protocol, a cryptographic protocol used by the Signal application
* Signal (IPC), a form of inter-process communication used in Unix and related operating systems
** C signal handling, a way for handling signals received by programs during their execution
* A term in functional reactive programming

### Communications

* Military communications, often called "signals"
* Recognition signal in human, technical or biological communications
* Signaling protocol to establish or tear down a connection, and to identify the state of the connection
* Signaling (telecommunications), a part of some communication protocols
* Smoke signal, an ancient form of communication
* Telegraphic signal, in telegraphy

#### Communication for transport

* International Code of Signals, a standard for sending signals by displaying flags
** Maritime flag signalling, generally flaghoist signalling, by which ships communicate with each other
** Naval flag signalling, covers various forms of flag signalling, such as semaphore or flaghoist
* Railway signal
* Traffic light

## Arts and entertainment

* Signal (magazine), a Wehrmacht propaganda magazine which was published in occupied Europe during World War II
* SIGNAL (US magazine), publication of the Armed Forces Communications and Electronics Association
* Signal, a New York Yiddish-language literary monthly published from 1933 to 1936 by the Communist Party USA
* Signal (novel), a 2009 children's novel about a boy who helps a girl from another planet signal her parents
* Signal (South Korean TV series), a 2016 South Korean police procedural TV series
* Signal (Japanese TV series), a 2018 Japanese police procedural TV series based on the 2016 South Korean series of the same name
* Signal – The Southeast Electronic Music Festival, an annual music festival held in the US
* Signal, Wyoming, a fictional town from the 2005 film Brokeback Mountain
* "Signals", a 2005 episode of the animated television series 12 oz. Mouse

### Music

* Signal (band), a Bulgarian rock band

#### Albums

* Signal (album), a 2005 album by Casiopea
* Signals (Mal Waldron album), 1971
* Signals (Mallory Knox album), the début album of the Mallory Knox band
* Signals (Rush album), 1982
* Signals (Wayne Krantz album), 1990
* Signals, an album by American band Devour the Day
* Signal (EP), a 2017 extended play by South Korean girl group Twice

#### Songs

* "Signal" (KAT-TUN song), a 2006 song by KAT-TUN
* "Signal" (Twice song), a 2017 song by Twice
* "Signals" (song), a 2021 song by Regard and Kwabs
* "Signal", a song by General Degree
* "Signal", a single by Stan Getz
* "Signal", a song from the 2006 Bollywood film Bhagam Bhag
* "Signal", a song by Sara Groves from the album Floodplain

## Places
### United States

* Signal, Arizona, a ghost town
* Signal, Missouri, a ghost town
* Signal, Ohio, an unincorporated community

## Organizations

* Signal Systems, a telecommunications company of the McLean Group of Companies
* Signal Foundation, a non-profit organization
* Signal Entertainment Group, a South Korean company

## Other uses

* Signal (bridge), a permitted means of conveying information to partner through the play of cards in contract bridge
* Citation signal, in law
* Signal (toothpaste)
* USS Signal, several US Navy ships
* Signal corps, military branch responsible for military communications