The term 'Ambulance Alert' is often used to refer to the sound of a SIREN, which is a loud, high-pitched noise that is used to alert people to an emergency situation. The crossword solution for this term is 'SIREN, ' which is a five-letter word. Sirens are typically used by emergency services such as ambulances, fire trucks, and police cars to alert people to their presence and to warn them of potential danger.