The Collaborative International Dictionary of English v.0.48:

Across \A*cross"\ (#; 115), prep. [Pref. a- + cross: cf. F. en
   croix. See Cross, n.]
   From side to side; athwart; crosswise, or in a direction
   opposed to the length; quite over; as, a bridge laid across a
   river. --Dryden.
   [1913 Webster]

   To come across, to come upon or meet incidentally.
      --Freeman.

   To go across the country, to go by a direct course across a
      region without following the roads.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Across \A*cross"\, adv.
   1. From side to side; crosswise; as, with arms folded across.
      --Shak.
      [1913 Webster]

   2. Obliquely; athwart; amiss; awry. [Obs.]
      [1913 Webster]

            The squint-eyed Pharisees look across at all the
            actions of Christ.                    --Bp. Hall.
      [1913 Webster]

WordNet (r) 3.0 (2006):

across
    adv 1: to the opposite side; "the football field was 300 feet
           across"
    2: transversely; "the marble slabs were cut across" [syn:
       across, crosswise, crossways]

Moby Thesaurus II by Grady Ward, 1.0:

51 Moby Thesaurus words for "across":
   across the grain, against, astraddle, astride, athwart,
   athwartships, bendwise, beyond, bias, biased, biaswise,
   catercorner, catercornered, confronting, contrariwise, contrawise,
   crisscross, cross, cross-grained, crossway, crossways, crosswise,
   diagonal, facing, fronting, horseback, in front of,
   in opposition to, kittycorner, oblique, obliquely, on,
   on horseback, over against, overthwart, past, sideways, sidewise,
   slant, straddle, straddle-legged, straddleback, thwart, thwartly,
   thwartways, toward, transversal, transverse, transversely,
   traverse, versus