elbow \el"bow\, n. as. elboga, elnboga akin to d. elleboga,
   ohg. elinbogo, g. ellbogen, ellenbogen, icel. ?lnbogi; prop.;
   arm-bend; eln ell orig., forearm + boga a bending. see 1st
   ell, and 4th bow.
   1. the joint or bend of the arm; the outer curve in the
      middle of the arm when bent.
      1913 webster

            her arms to the elbows naked.         --r. of
                                                  gloucester.
      1913 webster

   2. any turn or bend like that of the elbow, in a wall,
      building, and the like; a sudden turn in a line of coast
      or course of a river; also, an angular or jointed part of
      any structure, as the raised arm of a chair or sofa, or a
      short pipe fitting, turning at an angle or bent.
      1913 webster

   3. arch. a sharp angle in any surface of wainscoting or
      other woodwork; the upright sides which flank any paneled
      work, as the sides of windows, where the jamb makes an
      elbow with the window back. --gwilt.
      1913 webster

   note: elbow is used adjectively or as part of a compound, to
         denote something shaped like, or acting like, an elbow;
         as, elbow joint; elbow tongs or elbow-tongs; elbowroom,
         elbow-room, or elbow room.
         1913 webster

   at the elbow, very near; at hand.

   elbow grease, energetic application of force in manual
      labor. low

   elbow in the hawse naut., the twisting together of two
      cables by which a vessel rides at anchor, caused by
      swinging completely round once. --totten.

   elbow scissors surg., scissors bent in the blade or shank
      for convenience in cutting. --knight.

   out at elbow, with coat worn through at the elbows; shabby;
      in needy circumstances.
      1913 webster
see also:
ell bow at the elbow elbow grease elbow in the hawse elbow scissors 
out at elbow