rack rail
 齒軌


 Rack, n.
 1. An instrument or frame used for stretching, extending, retaining, or displaying, something. Specifically: (a) An engine of torture, consisting of a large frame, upon which the body was gradually stretched until, sometimes, the joints were dislocated; -- formerly used judicially for extorting confessions from criminals or suspected persons.
    During the troubles of the fifteenth century, a rack was introduced into the Tower, and was occasionally used under the plea of political necessity.   --Macaulay.
 (b) An instrument for bending a bow. (c) A grate on which bacon is laid. (d) A frame or device of various construction for holding, and preventing the waste of, hay, grain, etc., supplied to beasts. (e) A frame on which articles are deposited for keeping or arranged for display; as, a clothes rack; a bottle rack, etc. (f) Naut. A piece or frame of wood, having several sheaves, through which the running rigging passes; -- called also rack block. Also, a frame to hold shot. (g) Mining A frame or table on which ores are separated or washed. (h) A frame fitted to a wagon for carrying hay, straw, or grain on the stalk, or other bulky loads. (i) A distaff.
 2. Mech. A bar with teeth on its face, or edge, to work with those of a wheel, pinion, or worm, which is to drive it or be driven by it.
 3. That which is extorted; exaction. [Obs.]
 Mangle rack. Mach. See under Mangle. n.
 Rack block. Naut. See def. 1 (f), above.
 Rack lashing, a lashing or binding where the rope is tightened, and held tight by the use of a small stick of wood twisted around.
 Rack rail Railroads, a toothed rack, laid as a rail, to afford a hold for teeth on the driving wheel of a locomotive for climbing steep gradients, as in ascending a mountain.
 Rack saw, a saw having wide teeth.
 Rack stick, the stick used in a rack lashing.
 To be on the rack, to suffer torture, physical or mental.
 To live at rack and manger, to live on the best at another's expense. [Colloq.]
 To put to the rack, to subject to torture; to torment.
    A fit of the stone puts a king to the rack, and makes him as miserable as it does the meanest subject.   --Sir W. Temple.