What is Signal?
{{wiktionary|signal}} {{TOCright}} '''Signal''', '''signals''' or '''signalling''' may refer to: == Scientific concepts == * [[Signal (electrical engineering)]], a varying quantity that can carry information over air or wires. * [[Signal processing]], the field of techniques used to extract information from signals * [[Signal (computing)]], an event, message, or data structure transmitted between computational processes * [[Cell signalling|Cell signalling (biology)]], the system of communication that governs basic cellular activities and coordinates cell actions * [[Signal (biology)]], electrochemical activity in an organism == Communications == * '''Signals''' used in various kinds of [[transport]]: ** [[traffic signal|Road traffic signal]] ** [[Railway signal]] ** [[Semaphore]] ** [[Beacon]] ** [[International maritime signal flags]], using the [[International Code of Signals]] * [[Signals (military)]], a historical name for the [[military communications]] * [[Signal corps]], the branch of military which operates with command, control and communications systems * [[Signalling theory]] in biology, how organisms signal their state to others * [[Distress signal]] * [[Smoke signal]] (See also [[:Category:Early telecommunications]]) * [[Signalling (telecommunications)]], a part of some communication protocols * [[Signal (recognition)]], a way of showing that a person [[wikt:recognize|recognize]]s something; such as the [[Color of the day (police)|Color of the day]] used by police. == Names == * [[Signal band|''Signal'' band]] A rock band from Northwest Indiana * [[Signal (band)|''Signal'' (band)]], a Bulgarian rock band * [[Signals (album)]], an album by progressive rock band Rush * [[Signal (magazine)|''Signal'' (magazine)]] * [[Signal (toothpaste)]] * ''[[Signal 1]]'' and ''[[Signal 2]]'' radio stations * [[Signal (subscription service)]], service that provided real-time stock quotes * ''Signaal'' (now [[Thales Group|Thales Nederland]]), a Netherlands-based defence company * Signal Systems, a company of the [[