The Collaborative International Dictionary of English v.0.48:

Exploration \Ex`plo*ra"tion\, n. [L. exploratio: cf. F.
   exploration.]
   The act of exploring, penetrating, or ranging over for
   purposes of discovery, especially of geographical discovery;
   examination; as, the exploration of unknown countries; (Med.)
   physical examination.
   [1913 Webster]

         "An exploration of doctrine."            --Bp. Hall.
   [1913 Webster]

WordNet (r) 3.0 (2006):

exploration
    n 1: to travel for the purpose of discovery [syn: exploration,
         geographic expedition]
    2: a careful systematic search
    3: a systematic consideration; "he called for a careful
       exploration of the consequences"

Moby Thesaurus II by Grady Ward, 1.0:

46 Moby Thesaurus words for "exploration":
   adventure, analysis, domiciliary visit, dragnet, emprise, enquiry,
   examination, expedition, forage, frisk, house-search, hunt,
   hunting, inquiry, inspection, investigation, mission, observation,
   perquisition, pilgrimage, posse, probe, quest, ransacking, recce,
   recco, recon, reconnaissance, reconnoiter, reconnoitering,
   research, review, rummage, scouting, scrutiny, search,
   search party, search warrant, search-and-destroy operation,
   searching, stalk, stalking, still hunt, study, survey,
   turning over