The Collaborative International Dictionary of English v.0.48:

Inside \In"side`\, prep. or adv.
   Within the sides of; in the interior; contained within; as,
   inside a house, book, bottle, etc.
   [1913 Webster]

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]

The Collaborative International Dictionary of English v.0.48:

Inside \In"side`\, n.
   1. The part within; interior or internal portion; content.
      [1913 Webster]

            Looked he o' the inside of the paper? --Shak.
      [1913 Webster]

   2. pl. The inward parts; entrails; bowels; hence, that which
      is within; private thoughts and feelings.
      [1913 Webster]

            Here's none but friends; we may speak
            Our insides freely.                   --Massinger.
      [1913 Webster]

   3. An inside passenger of a coach or carriage, as
      distinguished from one upon the outside. [Colloq. Eng.]
      [1913 Webster]

            So down thy hill, romantic Ashbourne, glides
            The Derby dilly, carrying three insides.
                                                  --Anti-Jacobin.
      [1913 Webster]

   Patent insides or Patent outsides, a name give to
      newspaper sheets printed on one side with general and
      miscellaneous matter, and furnished wholesale to offices
      of small newspapers, where the blank pages are filled up
      with recent and local news.
      [1913 Webster]

WordNet (r) 3.0 (2006):

inside
    adv 1: within a building; "in winter we play inside" [syn:
           inside, indoors] [ant: alfresco, out of doors,
           outdoors, outside]
    2: on the inside; "inside, the car is a mess" [syn: inside,
       within] [ant: outside]
    3: with respect to private feelings; "inwardly, she was raging"
       [syn: inwardly, inside] [ant: outwardly]
    4: in reality; "she is very kind at heart" [syn: at heart, at
       bottom, deep down, inside, in spite of appearance]
    adj 1: relating to or being on the side closer to the center or
           within a defined space; "he reached into his inside
           jacket pocket"; "inside out"; "an inside pitch is between
           home plate and the batter" [ant: outside]
    2: being or applying to the inside of a building; "an inside
       wall"
    3: confined to an exclusive group; "privy to inner knowledge";
       "inside information"; "privileged information" [syn:
       inside, inner, privileged]
    4: away from the outer edge; "an inner lahne"; "the inside lane"
    n 1: the region that is inside of something [syn: inside,
         interior] [ant: exterior, outside]
    2: the inner or enclosed surface of something [syn: inside,
       interior] [ant: exterior, outside]

Moby Thesaurus II by Grady Ward, 1.0:

107 Moby Thesaurus words for "inside":
   advantaged, advantageous, arranged, at, at bottom, auricular,
   backing, backwards, basically, between us, bosom, bowels, breast,
   by nature, center, center of life, central, clandestine, closet,
   confidential, contents, core, deep, deepest recesses, entrails,
   esoteric, esoteric reality, everted, exclusive, favorable, favored,
   fundamentally, guts, heart, heart of hearts, herein, hushed,
   imprisoned, in, in petto, in prison, incarcerated, indoor, inmost,
   inmost heart, inmost soul, innards, inner, inner landscape,
   inner life, inner man, inner nature, inner recess, inner self,
   innermost, inside of, inside out, insides, interior, interior man,
   intern, internal, internals, intestine, intimate, into, intrados,
   intrinsic, inward, inwards, lining, middle, nerve center,
   not for publication, off the record, penetralia, prearranged,
   preferential, preferred, private, privileged, privy, propitious,
   quick, recesses, reversed, sealed, secret, secret heart,
   secret place, secret places, soul, spirit, stomach, stuffing,
   therein, tripes, true being, true inwardness, under privilege,
   unpublishable, viscera, vital center, vital principle, vitals,
   within, withindoors