The Collaborative International Dictionary of English v.0.48:

Combat \Com"bat\, n. [Cf. F. combat.]
   1. A fight; a contest of violence; a struggle for supremacy.
      [1913 Webster]

            My courage try by combat, if thou dar'st. --Shak.
      [1913 Webster]

            The noble combat that 'twixt joy and sorrow was
            fought in Paulina.                    --Shak.
      [1913 Webster]

   2. (Mil.) An engagement of no great magnitude; or one in
      which the parties engaged are not armies.
      [1913 Webster]

   Single combat, one in which a single combatant meets a
      single opponent, as in the case of David and Goliath;
      also, a duel.

   Syn: A battle; engagement; conflict; contest; contention;
        struggle; fight, strife. See Battle, Contest.
        [1913 Webster]

WordNet (r) 3.0 (2006):

single combat
    n 1: a fight between two people; "in all armies there were
         officers who needed to prove their bravery by single
         combat"