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English definition of “signal”

signal

noun [C]  /ˈsɪɡ·nəl/ us  

signal noun [C] (ACTION)

an action, movement, or sound that gives information, a message, a warning, or an order: I tried to call but kept getting a busy signal. When the lieutenant gave the signal, five police officers charged into the apartment. In retrospect, looking at how she was acting, we should have been able to recognize the danger signals. A signal is also a device, often with lights, that shows people or vehicles whether to stop, go, or move carefully.

signal noun [C] (WAVE)

a series of energy waves that carry a sound, picture, or other information: a low-frequency radio signal

signal

adjective  /ˈsɪɡ·nəl/ fml us  

signal adjective (IMPORTANT)

unusual and important: You performed a signal service to our people, and we wish to express our gratitude.

signal

verb [I/T]  /ˈsɪɡ·nəl/ us  

signal verb [I/T] (MAKE MOVEMENT)

to make a movement, sound, etc. that gives information or tells people what to do: [I] When you learn to drive, you are told that you have to signal before you turn right or left. [T] The police officer signaled us to stop.
(Definition of signal from the Cambridge Academic Content Dictionary © Cambridge University Press)
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