[tool] Show IPA noun 1. an implement, especially one held in the hand, as a hammer, saw, or file, for performing or facilitating mechanical operations. 2. any instrument of manual operation. 3. the cutting or machining part of a lathe, planer, drill, or similar machine. 4. the machine itself; a machine tool. 5. anything used as a means of accomplishing a task or purpose: Education is a tool for su