The Collaborative International Dictionary of English v.0.48:

Confrontation \Con`fron*ta"tion\, n. [LL. confrontatio.]
   Act of confronting. --H. Swinburne.
   [1913 Webster]

WordNet (r) 3.0 (2006):

confrontation
    n 1: a bold challenge
    2: discord resulting from a clash of ideas or opinions
    3: a hostile disagreement face-to-face [syn: confrontation,
       encounter, showdown, face-off]
    4: the act of hostile groups opposing each other; "the
       government was not ready for a confrontation with the
       unions"; "the invaders encountered stiff opposition" [syn:
       confrontation, opposition]
    5: a focussed comparison; bringing together for a careful
       comparison

Moby Thesaurus II by Grady Ward, 1.0:

103 Moby Thesaurus words for "confrontation":
   allegory, analogy, antagonism, anteposition, antipathy, antithesis,
   audience, balancing, bargaining, bargaining session, clashing,
   collision, collision course, comparative anatomy,
   comparative degree, comparative grammar, comparative judgment,
   comparative linguistics, comparative literature,
   comparative method, compare, comparing, comparison, conclave,
   confab, confabulation, conference, conflict, confrontment,
   congress, consultation, contention, contradiction,
   contradistinction, contraindication, contraposition, contrariety,
   contrast, contrastiveness, convention, correlation, council,
   council fire, council of war, counterposition, cross-purposes,
   disagreement, discrepancy, discussion, distinction,
   distinctiveness, encounter, exchange of views,
   eyeball-to-eyeball encounter, high-level talk, hostility, huddle,
   inconsistency, inimicalness, interchange of views, interview,
   joining, likening, matching, meeting, metaphor, narrow squeak,
   near thing, near-miss, negotiations, news conference, opposing,
   oppositeness, opposition, opposure, oppugnance, oppugnancy,
   palaver, parallelism, parley, perversity, polar opposition,
   polarity, polarization, posing against, pourparler, powwow,
   press conference, proportion, relation, rencontre, repugnance,
   seance, session, showdown, simile, similitude, sitting, summit,
   summit conference, summitry, trope of comparison, weighing



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

CONFRONTATION, crim. law, practice. The act by which a witness is brought in
the presence of the accused, so that the latter may object to him, if he
can, and the former may know and identify the accused, and maintain the
truth in his presence. No man can be a witness unless confronted with the
accused, except by consent.