When an aircraft is referred to as "heavy," what does this denote?

When an aircraft is referred to as "heavy," it specifically denotes that the aircraft's maximum takeoff weight exceeds 255,000 pounds. This designation is crucial for air traffic control and operational considerations, as "heavy" aircraft have different performance characteristics compared to lighter aircraft, particularly in terms of wake turbulence and the required separation distances during takeoff and landing. This distinction ensures that appropriate safety measures are applied to maintain safe flight operations in busy airspaces. Understanding this classification is key for pilots, air traffic controllers, and aviation professionals to ensure effective communication and safe management of various aircraft types in the skies.