From The Free On-line Dictionary of Computing (8 July 2008) [foldoc]:
Motorola 680x0
680x0
<processor> Shorthand for any member for the Motorola 68000
family of microprocessors from Motorola, Inc. The "x"
stands for 0, 1, 2, 3, 4 or 6.
(1993-05-01)