Signal

Message or indication conveying information.

indication sign message

A signal is a message or indication that conveys information, often transmitted through a medium.

/ˈsɪɡ.nəl/

From Old French signal, from Late Latin signalum, from signum ‘mark, token’.

A signal is like a message sent using lights, sounds, or other ways to tell someone something, like when a traffic light turns red to stop cars.

The word 'signal' comes from the Latin word 'signalis', meaning conspicuous or noticeable
Semaphore, a system of visual signals using flags, was used extensively in the 19th century
Early warning systems often relied on signal fires or drums to alert communities of danger

What is a signal? It's a way of conveying information
What are examples of signals? Traffic lights, smoke signals, and radio waves are all examples
How do we use signals? We use them to communicate information quickly and reliably

notice cue symbol

communication information

flag gesture light sound

system network

communication informational