What term denotes an emergency distress signal?

The term "Mayday" is universally recognized as an emergency distress signal, primarily used in maritime and aviation contexts. When an individual or crew communicates "Mayday," they are indicating a life-threatening emergency that requires immediate assistance. This specific term conveys the urgency of the situation and is understood internationally, making it a critical part of safety communication protocols.

In contrast, while the other choices relate to emergencies, they do not have the same established significance. "Distress" is a general term that describes a state of danger or difficulty but does not serve as a formal call for help. "Panic" refers to a state of overwhelming fear or anxiety and does not have a standardized meaning as a signal for help. "Alert" can indicate a warning or notification but lacks the urgency implied by "Mayday" for emergency situations. Therefore, "Mayday" is the correct choice for denoting an emergency distress signal due to its specific usage and international recognition.