A children's game in which players take turns to place S's and O's on a grid, collecting points by creating an "SOS" sequence.
The conventional Morse code call made by a ship in distress.
An electromechanical or electronic bell, klaxon, chime, horn, speaker, strobe light or other device which warns people in a building of a possible fire or other condition requiring evacuation.
The sound or other warning made by a fire alarm.
An emergency response to a fire by the fire department with manpower and equipment.