Which spoken word serves as a distress signal for both international and U.S. inland waters?

The term "Mayday" is universally recognized as a distress signal in both international and U.S. inland waters. Its use is established within maritime radio communications to indicate a life-threatening emergency that requires immediate assistance. This term comes from the French "m'aider," meaning "help me," but its adoption as a distress call has transcended language barriers, ensuring that it is understood by mariners worldwide.

When transmitted, "Mayday" must be repeated three times to alert others to the urgency of the situation, signifying that the vessel or individual is facing grave danger. This standardized distress signal upholds the safety of mariners by providing a clear, concise means of communication that is globally recognized, allowing for swift response from other vessels and rescue services. Other terms like "Emergency," "Help," and "Signal" do not carry the same level of universally accepted meaning when it comes to calling for immediate aid on the water, making "Mayday" the correct and appropriate choice in this context.