The Collaborative International Dictionary of English v.0.48:

Cross \Cross\, v. t. [imp. & p. p. Crossed (kr[o^]st; 115); p.
   pr. & vb. n. Crossing.]
   1. To put across or athwart; to cause to intersect; as, to
      cross the arms.
      [1913 Webster]

   2. To lay or draw something, as a line, across; as, to cross
      the letter t.
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   3. To pass from one side to the other of; to pass or move
      over; to traverse; as, to cross a stream.
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            A hunted hare . . . crosses and confounds her former
            track.                                -- I. Watts.
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   4. To pass, as objects going in an opposite direction at the
      same time. "Your kind letter crossed mine." --J. D.
      Forbes.
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   5. To run counter to; to thwart; to obstruct; to hinder; to
      clash or interfere with.
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            In each thing give him way; cross him in nothing.
                                                  --Shak.
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            An oyster may be crossed in love.     -- Sheridan.
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   6. To interfere and cut off; to debar. [Obs.]
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            To cross me from the golden time I look for. --Shak.
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   7. To make the sign of the cross upon; -- followed by the
      reflexive pronoun; as, he crossed himself.
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   8. To cancel by marking crosses on or over, or drawing a line
      across; to erase; -- usually with out, off, or over; as,
      to cross out a name.
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   9. To cause to interbreed; -- said of different stocks or
      races; to mix the breed of.
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   To cross a check (Eng. Banking), to draw two parallel
      transverse lines across the face of a check, with or
      without adding between them the words "and company", with
      or without the words "not negotiable", or to draw the
      transverse lines simply, with or without the words "not
      negotiable" (the check in any of these cases being crossed
      generally). Also, to write or print across the face of a
      check the name of a banker, with or without the words "not
      negotiable" (the check being then crossed specially). A
      check crossed generally is payable only when presented
      through a bank; one crossed specially, only when presented
      through the bank mentioned. [Webster 1913 Suppl.]

   To cross one's path, to oppose one's plans. --Macaulay.
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The Collaborative International Dictionary of English v.0.48:

Crossing \Cross"ing\, n. [See Cross, v. t. ]
   1. The act by which anything is crossed; as, the crossing of
      the ocean.
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   2. The act of making the sign of the cross. --Bp. Hall.
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   3. The act of interbreeding; a mixing of breeds.
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   4. Intersection, as of two paths or roads.
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   5. A place where anything (as a stream) is crossed; a paved
      walk across a street, or a set of marks across the street
      pavement indicating that this is a designated location for
      pedestrians to cross.
      [1913 Webster +PJC]

   6. Contradiction; thwarting; obstruction.
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            I do not bear these crossings.        --Shak.
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WordNet (r) 3.0 (2006):

crossing
    n 1: traveling across
    2: a shallow area in a stream that can be forded [syn: ford,
       crossing]
    3: a point where two lines (paths or arcs etc.) intersect
    4: a junction where one street or road crosses another [syn:
       intersection, crossroad, crossway, crossing,
       carrefour]
    5: a path (often marked) where something (as a street or
       railroad) can be crossed to get from one side to the other
       [syn: crossing, crosswalk, crossover]
    6: (genetics) the act of mixing different species or varieties
       of animals or plants and thus to produce hybrids [syn:
       hybridization, hybridisation, crossbreeding,
       crossing, cross, interbreeding, hybridizing]
    7: a voyage across a body of water (usually across the Atlantic
       Ocean)

Moby Thesaurus II by Grady Ward, 1.0:

128 Moby Thesaurus words for "crossing":
   abjuration, abjurement, abrogation, absolute contradiction,
   annulment, approach, asymptote, bottleneck, bucking, carrefour,
   challenge, cloverleaf, collision course, commutation,
   concentralization, concentration, concourse, concurrence,
   confluence, conflux, congress, contention, contradiction,
   contraposition, contrary assertion, contravention, contraversion,
   controversion, convergence, converging, counteraction, countering,
   counterworking, course, crossbreeding, crosscurrent, crosspoint,
   crossroad, crosswalk, crossway, crosswise, cruise, denial,
   disaffirmation, disallowance, disavowal, disclaimer, disclamation,
   disownment, disproof, flyover, focalization, focus, forswearing,
   funnel, gainsaying, globe-trotting, going, grade crossing,
   head wind, hub, hybridism, hybridization, impugnation, impugnment,
   interbreeding, intercrossing, intersection, journeying, leg,
   level crossing, locomotion, meeting, miscegenation, mongrelism,
   motion, movement, moving, mutual approach, narrowing gap, negation,
   nullification, ocean trip, opposing, opposition, opposure,
   oppugnation, overcrossing, overpass, passage, progress, radius,
   rebutment, rebuttal, recantation, refusal, refutation, rejection,
   renunciation, repudiation, resistance, retractation, retraction,
   revocation, rotary, run, sail, sea trip, shakedown cruise, spokes,
   standing against, tangent, thwart, tourism, touristry,
   traffic circle, traject, trajet, transit, transversal, travel,
   traveling, traversal, traverse, undercrossing, undercurrent,
   viaduct, voyage