The Collaborative International Dictionary of English v.0.48:

Rural \Ru"ral\, a. [F., fr. L. ruralis, fr. rus, ruris, the
   country. Cf. Room space, Rustic.]
   1. Of or pertaining to the country, as distinguished from a
      city or town; living in the country; suitable for, or
      resembling, the country; rustic; as, rural scenes; a rural
      prospect.
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            Here is a rural fellow; . . .
            He brings you figs.                   --Shak.
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   2. Of or pertaining to agriculture; as, rural economy.
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   Rural dean. (Eccl.) See under Dean.

   Rural deanery (Eccl.), the state, office, or residence, of
      a rural dean.
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   Syn: Rustic.

   Usage: Rural, Rustic. Rural refers to the country itself;
          as, rural scenes, prospects, delights, etc. Rustic
          refers to the character, condition, taste, etc., of
          the original inhabitants of the country, who were
          generally uncultivated and rude; as, rustic manners; a
          rustic dress; a rustic bridge; rustic architecture,
          etc.
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                We turn
                To where the silver Thames first rural grows.
                                                  --Thomson.
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                Lay bashfulness, that rustic virtue, by;
                To manly confidence thy throughts apply.
                                                  --Dryden.
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WordNet (r) 3.0 (2006):

rural
    adj 1: living in or characteristic of farming or country life;
           "rural people"; "large rural households"; "unpaved rural
           roads"; "an economy that is basically rural" [ant:
           urban]
    2: of or relating to the countryside as opposed to the city;
       "rural electrification"; "rural free delivery"

Moby Thesaurus II by Grady Ward, 1.0:

46 Moby Thesaurus words for "rural":
   Arcadian, agrarian, agrestic, agricultural, agronomic, arable,
   arcadian, bucolic, campestral, countrified, country, exurban, farm,
   farming, genuine, geoponic, georgic, homespun, idyllic,
   inartificial, lowland, native, natural, naturelike, outland,
   pastoral, provincial, rustic, simple, sylvan, unadorned,
   unaffected, unartificial, unassuming, undesigning, undisguising,
   undissembling, undissimulating, unembellished, unfeigning,
   unpretending, unpretentious, unsophisticated, unspoiled,
   unvarnished, upland



Bouvier's Law Dictionary, Revised 6th Ed (1856):

RURAL. That which relates to the country, as rural servitudes. See Urban.