Source : Webster's Revised Unabridged Dictionary (1913)

Umpire \Um"pire\, v. i.
   To act as umpire or arbitrator.

Umpire \Um"pire\, n. [OE. nompere, nounpere (also impier, fr. F.
   impair uneven), fr. OF. nomper uneven, F. non-pair; hence the
   meaning, uneven, i. e., third person; non not + OF. per even,
   equal, peer, F. pair; cf. L. impar uneven, unequal. See
   {Non-}, and {Peer}, n.]
   1. A person to whose sole decision a controversy or question
      between parties is referred; especially, one chosen to see
      that the rules of a game, as cricket, baseball, or the
      like, are strictly observed.

            A man, in questions of this kind, is able to be a
            skillful umpire between himself and others.
                                                  --Barrow.

   2. (Law) A third person, who is to decide a controversy or
      question submitted to arbitrators in case of their
      disagreement. --Blackstone.

   Syn: Judge; arbitrator; referee. See {Judge}.

Umpire \Um"pire\, v. t. [imp. & p. p. {Umpired}; p. pr. & vb. n.
   {Umpiring}.]
   1. To decide as umpire; to arbitrate; to settle, as a
      dispute.

            Judges appointed to umpire the matter in contest
            between them, and to decide where the right lies.
                                                  --South.

   2. To perform the duties of umpire in or for; as, to umpire a
      game. [Colloq.]

Source : WordNet®

umpire
     n : an official at a baseball game [syn: {ump}]
     v : be a referee or umpire in a sports competition [syn: {referee}]