File n.
 1. A steel instrument, having cutting ridges or teeth, made by indentation with a chisel, used for abrading or smoothing other substances, as metals, wood, etc.
 Note: ☞ A file differs from a rasp in having the furrows made by straight cuts of a chisel, either single or crossed, while the rasp has coarse, single teeth, raised by the pyramidal end of a triangular punch.
 2. Anything employed to smooth, polish, or rasp, literally or figuratively.
    Mock the nice touches of the critic's file.   --Akenside.
 3. A shrewd or artful person. [Slang]
    Will is an old file in spite of his smooth face.   --Thackeray.
 Bastard file, Cross file, etc. See under Bastard, Cross, etc.
 Cross-cut file, a file having two sets of teeth crossing obliquely.
 File blank, a steel blank shaped and ground ready for cutting to form a file.
 File cutter, a maker of files.
 Second-cut file, a file having teeth of a grade next finer than bastard.
 Single-cut file, a file having only one set of parallel teeth; a float.
 Smooth file, a file having teeth so fine as to make an almost smooth surface.