Source : Webster's Revised Unabridged Dictionary (1913)

Plaint \Plaint\, n. [OE. plainte, pleynte, F. plainte, fr. L.
   plangere, planctum (plancta, fem. p. p.), to beat, beat the
   breast, lament. Cf. {Complain}, {Plague}, {Plangent}.]
   1. Audible expression of sorrow; lamentation; complaint;
      hence, a mournful song; a lament. --Chaucer.``The
      Psalmist's mournful plaint.'' --Wordsworth.

   2. An accusation or protest on account of an injury.

            There are three just grounds of war with Spain: one
            of plaint, two upon defense.          --Bacon.

   3. (Law) A private memorial tendered to a court, in which a
      person sets forth his cause of action; the exhibiting of
      an action in writing. --Blackstone.

Source : WordNet®

plaint
     n 1: a written statement of the grounds of complaint made to
          court law asking for the grievance to be redressed
     2: a cry of sorrow and grief; "their pitiful laments could be
        heard throughout the ward" [syn: {lament}, {lamentation},
        {wail}]