The Collaborative International Dictionary of English v.0.48:

Mop \Mop\, n. [CF. W. mop, mopa, Ir. moipal, Gael. moibeal,
   moibean; or OF. mappe a napkin (see Map, Napkin).]
   1. An implement for washing floors, or the like, made of a
      piece of cloth, or a collection of thrums, or coarse yarn,
      fastened to a handle.
      [1913 Webster]

   2. A fair where servants are hired. [Prov. Eng.]
      [1913 Webster]

   3. The young of any animal; also, a young girl; a moppet.
      [Prov. Eng.] --Halliwell.
      [1913 Webster]

   Mop head.
      (a) The end of a mop, to which the thrums or rags are
          fastened.
      (b) A clamp for holding the thrums or rags of a mop.
          [U.S.]
          [1913 Webster]