1. An intermediary computer that does set-up and filtering for another (usually
more powerful but less friendly) machine (a "back end").
2. Software that provides an interface to another program "behind" it, which may
not be as user-friendly. Probably from analogy with hardware front-ends that
interfaced with mainframes.
Frobozz Magic Programming Language « frogging «
front end » front-end processor » front side bus