startsignal
nounUK /ˈstɑːtˌsɪɡnəl/
US /ˈstɑːrtˌsɪɡnəl/
A start signal is a sound or sign that tells everyone it is time to begin.
When the referee blew the whistle, it was the start signal for the race.
OTHER MEANINGS
2. An electronic pulse that makes a machine or device begin working.
The computer sent a start signal to the printer.
3. A radio or light signal that tells a rocket or vehicle to launch.
The control room gave the start signal, and the rocket lifted off.
4. A sign in a game or sport that play is about to begin.
The buzzer was the start signal for the second half.