The 68040 is the first 680x0 family member with an on-chip FPU (floating point unit). It thus includes all of the functionality that previously required external chips, namely the FPU and MMU (which was added in the 030). It also has split instruction and data caches of 4 kilobytes each. It is fully pipelined, with six stages.
Versions of the '040' were created for specific market segments, including the 68LC040 which removed the FPU, and the 68EC040 which removed both the FPU and MMU. Various versions were used in the Amiga and Apple Macintosh Quadra series of personal computers, as well as being used in a number of Workstations and later versions of the NeXT computers.
For more information on the instructions and architecture, see Motorola 68000.
In keeping with general Motorola naming, this CPU is often referred to as the 040.