Source : Webster's Revised Unabridged Dictionary (1913)

Allegation \Al`le*ga"tion\, n. [L. allegatio, fr. allegare,
   allegatum, to send a message, cite; later, to free by giving
   reasons; ad + legare to send, commission. Cf. {Allege} and
   {Adlegation}.]
   1. The act of alleging or positively asserting.

   2. That which is alleged, asserted, or declared; positive
      assertion; formal averment

            I thought their allegation but reasonable. --Steele.

   3. (Law) A statement by a party of what he undertakes to
      prove, -- usually applied to each separate averment; the
      charge or matter undertaken to be proved.

Source : WordNet®

allegation
     n 1: (law) a formal accusation against somebody (often in a court
          of law); "an allegation of malpractice"
     2: statements affirming or denying certain matters of fact that
        you are prepared to prove [syn: {allegement}]