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 work to 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)