How is the Center of Gravity defined in aviation?

The Center of Gravity (CG) in aviation is defined as the point where an aircraft would balance. This is crucial for the stability and control of the aircraft during flight. When the CG is within the specified limits, the aircraft will behave predictably and respond correctly to the pilot's control inputs. Maintaining the correct balance ensures that the aircraft can achieve optimal performance, as an improperly balanced aircraft can lead to difficulty in controlling the pitch and roll, potentially resulting in an unsafe flying condition.

The concept of balance at the CG takes into account the distribution of weight across the aircraft. If the CG is too far forward or aft, it may lead to undesirable flight characteristics such as excessive nose-up or nose-down attitudes. Therefore, understanding the position of the CG and how it can shift with changes in loading or fuel consumption is vital for safe flight operations.

While other options mentioned concepts related to weight and structure, they do not accurately capture the essence of what the Center of Gravity represents in terms of balance and stability in an aircraft.