1. A program used primarily to create, manipulate, modify, or analyse other programs, such as a compiler or an editor or a cross-referencing program.Opposite: app, operating system.2. A Unixapplication program with a simple, "transparent" (typically text-stream) interface designed specifically to be used in programmed combination with other tools (see filter, plumbing).3. (MIT: general to students there) To workto study (connotes tedium).The TMRC Dictionary defined this as "to set one' s brain to the grindstone".See hack.4. (MIT) A student who studies too much and hacks too little.MIT' s student humour magazine rejoices in the name "Tool and Die".[Jargon File](1996-12-12)