Today's (FAA) Definition
of "Large" and "Small" Aircraft.

Small Multi-Engine Aircraft are defined as:
All multi-engine, fixed wing airplanes of 12,500 pounds or less maximum certificated takeoff weight.
Also includes normal category with SFAR 41 certification, propeller driven, multi-engine, fixed wing airplanes in excess of 12,500 pounds certificated takeoff weight and commuter category, propeller driven, multi-engine, fixed wing airplanes of 19,000 pounds or less maximum certificated takeoff weight.

Large Multi-Engine Aircraft are defined as:
All multi-engine, fixed wing airplanes of more than 12,500 pounds maximum certificated takeoff weight.
Also includes normal category with SFAR 41 certification, propeller driven, multi-engine, fixed wing airplanes in excess of 12,500 pounds certificated takeoff weight and commuter category, propeller driven, multiengine, fixed wing airplanes of 19,000 pounds or less maximum certificated takeoff weight.

Note: The text highlighted is Dark Red is identical.