The Collaborative International Dictionary of English v.0.48:

Jim-crow \Jim"-crow`\, a.
   For negroes only; set aside for used of negroes as a policy
   of racial discrimination.
   [PJC]

The Collaborative International Dictionary of English v.0.48:

Jim-crow \Jim"-crow`\, n. (Mach.)
   1. A machine for bending or straightening rails.
      [1913 Webster]

   2. A planing machine with a reversing tool, to plane both
      ways.
      [1913 Webster]