The Collaborative International Dictionary of English v.0.48:

Overview \O"ver*view`\, n. [Cf. Survey.]
   1. An inspection or overlooking. [Obs.] --Shak.
      [1913 Webster]

   2. A brief summary of a topic, situation, or plan; an outline
      or survey[2].
      [PJC]

WordNet (r) 3.0 (2006):

overview
    n 1: a general summary of a subject; "the treasurer gave a brief
         overview of the financial consequences"

Moby Thesaurus II by Grady Ward, 1.0:

37 Moby Thesaurus words for "overview":
   abbreviation, abbreviature, abrege, abridgment, abstract, brief,
   capsule, compend, condensation, condensed version, conspectus,
   contemplation, digest, draft, epitome, examination,
   eyeball inspection, head, inspection, ocular inspection, outline,
   pandect, precis, review, rubric, scrutiny, shortened version,
   skeleton, sketch, survey, syllabus, synopsis, the eye,
   thumbnail sketch, topical outline, vetting, visual examination