The Collaborative International Dictionary of English v.0.48:

Encounter \En*coun"ter\, v. t. [imp. & p. p. Encountered; p.
   pr. & vb. n. Encountering.] [OF. encontrer; pref. en- (L.
   in) + contre against, L. contra. See Counter, adv.]
   To come against face to face; to meet; to confront, either by
   chance, suddenly, or deliberately; especially, to meet in
   opposition or with hostile intent; to engage in conflict
   with; to oppose; to struggle with; as, to encounter a friend
   in traveling; two armies encounter each other; to encounter
   obstacles or difficulties, to encounter strong evidence of a
   truth.
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         Then certain philosophers of the Epicureans, and of the
         Stoics, encountered him.                 --Acts xvii.
                                                  18.
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         I am most fortunate thus accidentally to encounter you.
                                                  --Shak.
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The Collaborative International Dictionary of English v.0.48:

Encounter \En*coun"ter\, v. i.
   To meet face to face; to have a meeting; to meet, esp. as
   enemies; to engage in combat; to fight; as, three armies
   encountered at Waterloo.
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         I will encounter with Andronicus.        --Shak.
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         Perception and judgment, employed in the investigation
         of all truth, have in the first place to encounter with
         particulars.                             --Tatham.
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The Collaborative International Dictionary of English v.0.48:

Encounter \En*coun"ter\, n. [OF. encontre, fr. encontrer. See
   Encounter, v. t.]
   1. A meeting face to face; a running against; a sudden or
      incidental meeting; an interview.
      [1913 Webster]

            To shun the encounter of the vulgar crowd. --Pope.
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   2. A meeting, with hostile purpose; hence, a combat; a
      battle; as, a bloody encounter.
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            As one for . . . fierce encounters fit. --Spenser.
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            To join their dark encounter in mid-air. --Milton
      .

   Syn: Contest; conflict; fight; combat; assault; rencounter;
        attack; engagement; onset. See Contest.
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WordNet (r) 3.0 (2006):

encounter
    n 1: a minor short-term fight [syn: brush, clash,
         encounter, skirmish]
    2: a casual or unexpected convergence; "he still remembers their
       meeting in Paris"; "there was a brief encounter in the
       hallway" [syn: meeting, encounter]
    3: a casual meeting with a person or thing [syn: encounter,
       coming upon]
    4: a hostile disagreement face-to-face [syn: confrontation,
       encounter, showdown, face-off]
    v 1: come together; "I'll probably see you at the meeting"; "How
         nice to see you again!" [syn: meet, run into,
         encounter, run across, come across, see]
    2: come upon, as if by accident; meet with; "We find this idea
       in Plato"; "I happened upon the most wonderful bakery not
       very far from here"; "She chanced upon an interesting book in
       the bookstore the other day" [syn: find, happen,
       chance, bump, encounter]
    3: be beset by; "The project ran into numerous financial
       difficulties" [syn: run into, encounter]
    4: experience as a reaction; "My proposal met with much
       opposition" [syn: meet, encounter, receive]
    5: contend against an opponent in a sport, game, or battle;
       "Princeton plays Yale this weekend"; "Charlie likes to play
       Mary" [syn: meet, encounter, play, take on]