What does turn on the siren mean?
turn on the siren
Synonyms: put the siren on
Definition
To switch on a siren so that it gives its loud warning wail.
Example sentences
At the fire station's open day they let us climb into the ambulance, and my husband couldn't resist turning on the siren.
The second they turned on the siren, the cars in front of us made way — it was like the Red Sea parting.