Source : Webster's Revised Unabridged Dictionary (1913)

Ravel \Rav"el\, v. t. [imp. & p. p. {Raveled}or {Ravelled}; p.
   pr. & vb. n. {Raveling} or {Ravelling}.] [. ravelen, D.
   rafelen, akin to LG. rebeln, rebbeln, reffeln.]
   1. To separate or undo the texture of; to take apart; to
      untwist; to unweave or unknit; -- often followed by out;
      as, to ravel a twist; to ravel out a sticking.

Raveling \Rav"el*ing\, n. [Also ravelling.]
   1. The act of untwisting, or of disentangling.

   2. That which is raveled out; esp., a thread detached from a
      texture.

Source : WordNet®

raveling
     n : a bit of fiber that has become separated from woven fabric
         [syn: {ravelling}]