The Collaborative International Dictionary of English v.0.48:

Inside \In"side`\, a.
   1. Being within; included or inclosed in anything; contained;
      interior; internal; as, the inside passengers of a
      stagecoach; inside decoration.
      [1913 Webster]

            Kissing with inside lip.              --Shak.
      [1913 Webster]

   2. Adapted to the interior.
      [1913 Webster]

   Inside callipers (Mech.), callipers for measuring the
      diameters of holes, etc.

   Inside finish (Arch.), a general term for the final work in
      any building necessary for its completion, but other than
      unusual decoration; thus, in joiner work, the doors and
      windows, inside shutters, door and window trimmings,
      paneled jams, baseboards, and sometimes flooring and
      stairs; in plaster work, the finishing coat, the cornices,
      centerpieces, etc.,; in painting, all simple painting of
      woodwork and plastering.

   Inside track, the inner part of a race course; hence,
      colloquially, advantage of place, facilities, contacts,
      etc., in competition.
      [1913 Webster]

WordNet (r) 3.0 (2006):

inside track
    n 1: a favorable position in a competition; "the boss's son had
         the inside track for that job"
    2: the inner side of a curved racecourse

Moby Thesaurus II by Grady Ward, 1.0:

24 Moby Thesaurus words for "inside track":
   advantage, bulge, coign of vantage, drag, drop, edge, favor,
   flying start, head start, interest, jump, odds, pull,
   running start, something extra, something in reserve,
   special favor, start, suction, upper hand, vantage, vantage ground,
   vantage point, whip hand