The Collaborative International Dictionary of English v.0.48:

Littoral \Lit"to*ral\, a. [L. littoralis, litoralis, from
   littus, litus, the seashore: cf. F. littoral.]
   1. Of or pertaining to a shore, as of the sea.
      [1913 Webster]

   2. (Biol.) Inhabiting the seashore, esp. the zone between
      high-water and low-water mark.
      [1913 Webster]

WordNet (r) 3.0 (2006):

littoral
    adj 1: of or relating to a coastal or shore region
    n 1: the region of the shore of a lake or sea or ocean [syn:
         littoral, litoral, littoral zone, sands]

Moby Thesaurus II by Grady Ward, 1.0:

78 Moby Thesaurus words for "littoral":
   aquatic, balneal, bank, beach, benthic zone, berm, bordering,
   borderline, boundary, bounding, coast, coastal, coastland,
   coastline, deep-sea, determinant, determinative, determining,
   embankment, estuarine, estuarine area, extreme, foreshore,
   fringing, frontier, grallatorial, intertidal zone, ironbound coast,
   lido, limbic, liminal, limit, limiting, marginal, natant,
   natatorial, natatory, pelagic zone, plage, playa, rimming,
   riparial, riparian, riparious, riverside, riviera, rockbound coast,
   sands, sea margin, seabank, seabeach, seaboard, seacliff, seacoast,
   seashore, seaside, shingle, shore, shoreline, shoreside, shoreward,
   skirting, splash zone, strand, sublittoral, submerged coast,
   supralittoral, swimming, terminal, threshold, tidal, tidewater,
   water-dwelling, water-growing, water-living, water-loving,
   waterfront, waterside