The Collaborative International Dictionary of English v.0.48:

Skeleton \Skel"e*ton\, n. [NL., fr. Gr. ???? (sc. ???) a dried
   body, a mummy, fr. ???? dried up, parched, ???? to dry, dry
   up, parch.]
   1. (Anat.)
      (a) The bony and cartilaginous framework which supports
          the soft parts of a vertebrate animal.

   Note: [See Illust. of the Human Skeleton, in Appendix.]
      (b) The more or less firm or hardened framework of an
          invertebrate animal.
          [1913 Webster]

   Note: In a wider sense, the skeleton includes the whole
         connective-tissue framework with the integument and its
         appendages. See Endoskeleton, and Exoskeleton.
         [1913 Webster]

   2. Hence, figuratively:
      (a) A very thin or lean person.
      (b) The framework of anything; the principal parts that
          support the rest, but without the appendages.
          [1913 Webster]

                The great skeleton of the world.  --Sir M. Hale.
          [1913 Webster]
      (c) The heads and outline of a literary production,
          especially of a sermon.
          [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Skeleton \Skel"e*ton\, a.
   Consisting of, or resembling, a skeleton; consisting merely
   of the framework or outlines; having only certain leading
   features of anything; as, a skeleton sermon; a skeleton
   crystal.
   [1913 Webster]

   Skeleton bill, a bill or draft made out in blank as to the
      amount or payee, but signed by the acceptor. [Eng.]

   Skeleton key, a key with nearly the whole substance of the
      web filed away, to adapt it to avoid the wards of a lock;
      a master key; -- used for opening locks to which it has
      not been especially fitted.

   Skeleton leaf, a leaf from which the pulpy part has been
      removed by chemical means, the fibrous part alone
      remaining.

   Skeleton proof, a proof of a print or engraving, with the
      inscription outlined in hair strokes only, such proofs
      being taken before the engraving is finished.

   Skeleton regiment, a regiment which has its complement of
      officers, but in which there are few enlisted men.

   Skeleton shrimp (Zool.), a small crustacean of the genus
      Caprella. See Illust. under Laemodipoda.
      [1913 Webster]

WordNet (r) 3.0 (2006):

skeleton
    n 1: something reduced to its minimal form; "the battalion was a
         mere skeleton of its former self"; "the bare skeleton of a
         novel"
    2: a scandal that is kept secret; "there must be a skeleton
       somewhere in that family's closet" [syn: skeleton,
       skeleton in the closet, skeleton in the cupboard]
    3: the hard structure (bones and cartilages) that provides a
       frame for the body of an animal [syn: skeletal system,
       skeleton, frame, systema skeletale]
    4: the internal supporting structure that gives an artifact its
       shape; "the building has a steel skeleton" [syn: skeleton,
       skeletal frame, frame, underframe]

Moby Thesaurus II by Grady Ward, 1.0:

167 Moby Thesaurus words for "skeleton":
   abbreviation, abbreviature, abrege, abridgment, abstract,
   adumbrate, anatomy, appendicular skeleton, ashes, axial skeleton,
   backing, barebones, bean pole, beanstalk, bearing, block out,
   blueprint, body, bones, brief, broomstick, brouillon, bushing,
   cadaver, cadre, capsule, carcass, carrion, cartoon, case, casement,
   casing, chalk, chart, chassis, clay, clothes pole, compend,
   condensation, condensed version, configuration, conspectus,
   contour, copy, corpse, corpus delicti, crowbait, dead body,
   dead man, dead person, decedent, delineation, design, diagram,
   digest, doorframe, draft, drawing, dry bones, dust, earth, ebauche,
   elevation, embalmed corpse, epitome, esquisse, exoskeleton, fabric,
   features, figuration, figure, food for worms, frame, framework,
   framing, gestalt, graph, ground plan, gruel, head, house plan,
   hulk, ichnography, infrastructure, lanky, late lamented, lath,
   lattice, latticework, lineaments, lines, main features,
   mere shadow, mere wreck, mortal remains, mount, mounting,
   mummification, mummy, nervous wreck, organic remains, outline,
   overview, pandect, paper, pattern, picture frame, plot, precis,
   profile, projection, rail, rake, rattlebones, rattletrap, relics,
   relief, reliquiae, remains, review, rough, rubric, ruin, ruins,
   sash, setting, shadow, shapes, shaving, shell, shortened version,
   silhouette, skeletal, sketch, slat, slim, slip, soup, spindlelegs,
   spindleshanks, splinter, stack of bones, stiff, stilt, streak,
   survey, syllabus, synopsis, table, tenement of clay, the dead,
   the deceased, the defunct, the departed, the loved one,
   thumbnail sketch, topical outline, tournure, twiggy, underframe,
   vein, wafer, walking skeleton, window case, window frame,
   working drawing, wreck