signaler
nounUK /ˈsɪɡnələ/
US /ˈsɪɡnələr/
A signaler is a person who gives a sign or message to others.
The signaler waved a flag to tell the train to stop.
OTHER MEANINGS
2. A device or person that sends signals, especially in the military or on railways.
The signaler at the station raised the green flag.
3. Someone who makes something known or points something out.
She was the first signaler of the problem to the manager.
4. In biology, a molecule or cell that sends a signal to other cells.
The signaler released a chemical that alerted nearby cells.