The term 'Defense Arm' can be broken down into two parts: NAVY and Defense. The NAVY is a branch of the United States Armed Forces responsible for naval operations, including the protection of the country's coasts and waterways. It is one of the oldest branches of the military, having been established in 1775. The Defense part of the term refers to the protection of the nation from external threats, such as foreign powers or terrorist organizations. The NAVY plays an important role in this defense, providing ships, aircraft, and personnel to protect the country's interests.