driver

n. 1. The main loop of an event-processing program; the code that gets
commands and dispatches them for execution. 2. [techspeak] In device driver
, code designed to handle a particular peripheral device such as a magnetic
disk or tape unit. 3. In the TeX world and the computerized typesetting
world in general, a program that translates some device-independent or other
common format to something a real device can actually understand.

