What is the correct term for the ceremonial day each ship commemorates its historical achievements?

The term "Anniversary" is used to describe the ceremonial day each ship commemorates its historical achievements. This event typically marks the date when the ship was launched or officially commissioned into service. It serves as an opportunity for the crew and the commanding officers to reflect on the ship's history, honor its accomplishments, and recognize the contributions of those who have served onboard over the years. Celebrating an anniversary is not only a recognition of the ship's operational milestones but also a time to foster pride and camaraderie among the crew.

While "milestone," "commemoration," and "foundation day" may relate to significant events or occasions, they do not specifically signify the annual recognition of a ship's commissioning or launch, which is the essence of what an anniversary represents. Therefore, "Anniversary" is the most appropriate and widely accepted term for this ceremonial occasion.