Definition of signal noun from the Oxford Advanced Learner's Dictionary

      

    signal

     noun
    noun
    BrE BrE//ˈsɪɡnəl//
     
    ; NAmE NAmE//ˈsɪɡnəl//
     
    Radio technology, Controlling traffic, Mobile devices, Watching TV
     
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  1. 1  a movement or sound that you make to give somebody information, instructions, a warning, etc. synonym sign a danger/warning/distress, etc. signal At an agreed signal they left the room. The siren was a signal for everyone to leave the building. When I give the signal, run! (North American English) All I get is a busy signal when I dial his number (= his phone is being used). hand signals (= movements that cyclists and drivers make with their hands to tell other people that they are going to stop, turn, etc.) see also turn signal
  2. 2  an event, an action, a fact, etc. that shows that something exists or is likely to happen synonym indication The rise in inflation is a clear signal that the government's policies are not working. Chest pains can be a warning signal of heart problems. Reducing prison sentences would send the wrong signals to criminals. Synonymssignindication symptom symbol indicator signalThese are all words for an event, action or fact that shows that something exists, is happening or may happen in the future.sign an event, action or fact that shows that something exists, is happening or may happen in the future:Headaches may be a sign of stress.indication (rather formal) a remark or sign that shows that something is happening or what somebody is thinking or feeling:They gave no indication as to how the work should be done.sign or indication?An indication often comes in the form of something that somebody says; a sign is usually something that happens or something that somebody does.symptom a change in your body or mind that shows that you are not healthy; a sign that something exists, especially something bad:Symptoms include a sore throat. The rise in inflation was just one symptom of the poor state of the economy.symbol a person, object or event that represents a more general quality or situation:The dove is a universal symbol of peace.indicator (rather formal) a sign that shows you what something is like or how a situation is changing:the economic indicatorssignal an event, action or fact that shows that something exists, is happening or may happen in the future:Chest pains can be a warning signal of heart problems.sign or signal? Signal is often used to talk about an event, action or fact that suggests to somebody that they should do something. Sign is not usually used in this way:Reducing prison sentences would send the wrong signs to criminals.Patterns a(n) sign/​indication/​symptom/​symbol/​indicator/​signal of something a(n) sign/​indication/​symptom/​indicator/​signal that… a clear sign/​indication/​symptom/​symbol/​indicator/​signal an obvious sign/​indication/​symptom/​symbol/​indicator an early sign/​indication/​symptom/​indicator/​signal an outward sign/​indication/​symbol to give a(n) sign/​indication/​signal
  3. 3  a piece of equipment that uses different coloured lights to tell drivers to go slower, stop, etc., used especially on railways/railroads and roads traffic signals a stop signal Delays are occurring as a result of signal failure on the northbound line. See related entries: Controlling traffic
  4. 4  a series of electrical waves that carry sounds, pictures or messages, for example to a radio, television or mobile/cell phone TV signals a high-frequency signal a radar signal to detect/pick up signals to emit a signal I couldn't get a signal on my cell phone. The satellite is used for transmitting signals around the world. See related entries: Radio technology, Mobile devices, Watching TV
  5. Word Originnoun late Middle English: from Old French, from medieval Latin signale, neuter of late Latin signalis, from Latin signum ‘mark, token’. The verb dates from the early 19th cent.Extra examples A strong buy signal was issued to traders. All I get is a busy signal when I dial his number. At a pre-arranged signal, everyone started cheering. He had arranged a signal for the band to begin. Interviewers quickly learn to pick up non-verbal signals. It is possible to jam GPS signals in battle. Laughing when you should be crying sends out the wrong signals to people. She made a signal for the car to stop. The brain interprets the signals from the retina as light. The digital signal travels down wires to the server. The insect’s bright colours act as warning signals to its predators. The insect’s yellow spots act as a warning signal to its predators. The nerves carry these signals to the brain. The remark was interpreted as a signal that their government was ready to return to the peace talks. The signal is scrambled into code before it is sent. The traffic signals were on red. This equipment can detect very low frequency signals. Try to read the signals coming from the patient. Wait for the signal from the leader of your group. When I give the signal, run! a faint signal from the satellite the signals that can indicate danger The rise in inflation is a clear signal that the government’s policies are not working. a danger/​distress signal hand signals
See the Oxford Advanced American Dictionary entry: signal