The Collaborative International Dictionary of English v.0.48:

Pigtail \Pig"tail`\, n.
   1. The tail of a pig.
      [1913 Webster]

   2. (Hair Dressing) A cue, or queue. --J. & H. Smith.
      [1913 Webster]

   3. A kind of twisted chewing tobacco.
      [1913 Webster]

            The tobacco he usually cheweth, called pigtail.
                                                  --Swift.
      [1913 Webster]

WordNet (r) 3.0 (2006):

pigtail
    n 1: a plait of braided hair

Moby Thesaurus II by Grady Ward, 1.0:

32 Moby Thesaurus words for "pigtail":
   braid, brush, bun, cauda, caudal appendage, caudation, cavendish,
   chaw, chew, chewing tobacco, chignon, coil, cud, cue, cut plug,
   dock, eating tobacco, fantail, fid, knot, navy, navy plug, plait,
   queue, quid, rattail, stub, tail, tailpiece, tobacco juice,
   topknot, twist