By that logic, the 6502 is a 16-bit CPU, because it (and just about every other CPU we call 8-bit) has a 16-bit address bus. The 68000 has a 16-bit data bus an

By that logic, the 6502 is a 16-bit CPU, because it (and just about every other CPU we call 8-bit) has a 16-bit address bus. The 68000 has a 16-bit data bus and ALU, a 24-bit address bus, and 32-bit registers, but is usually considered a 16-bit CPU. I guess for older CPUs, the data bus and the ALU size are the determining factors.