Source : Webster's Revised Unabridged Dictionary (1913)

Harp \Harp\, n. [OE. harpe, AS. hearpe; akin to D. harp, G.
   harfe, OHG. harpha, Dan. harpe, Icel. & Sw. harpa.]
   1. A musical instrument consisting of a triangular frame
      furnished with strings and sometimes with pedals, held
      upright, and played with the fingers.

   2. (Astron.) A constellation; Lyra, or the Lyre.

   3. A grain sieve. [Scot.]

   {[AE]olian harp}. See under {[AE]olian}.

   {Harp seal} (Zo["o]l.), an arctic seal ({Phoca
      Gr[oe]nlandica}). The adult males have a light-colored
      body, with a harp-shaped mark of black on each side, and
      the face and throat black. Called also {saddler}, and
      {saddleback}. The immature ones are called {bluesides}.

Harp \Harp\, v. i. [imp. & p. p. {Harped}p. pr. & vb. n.
   {Harping}.] [AS. hearpian. See {Harp}, n.]
   1. To play on the harp.

            I heard the voice of harpers, harping with their
            harps.                                --Rev. xiv. 2.

   2. To dwell on or recur to a subject tediously or
      monotonously in speaking or in writing; to refer to
      something repeatedly or continually; -- usually with on or
      upon. ``Harpings upon old themes.'' --W. Irving.

            Harping on what I am, Not what he knew I was.
                                                  --Shak.

   {To harp on one string}, to dwell upon one subject with
      disagreeable or wearisome persistence. [Collog.]

Harp \Harp\, v. t.
   To play on, as a harp; to play (a tune) on the harp; to
   develop or give expression to by skill and art; to sound
   forth as from a harp; to hit upon.

         Thou 'harped my fear aright.             --Shak.

Source : WordNet®

harp
     n 1: a chordophone that has a triangular frame consisting of a
          sounding board and a pillar and a curved neck; the
          strings stretched between the neck and the soundbox are
          plucked with the fingers
     2: a pair of curved vertical supports for a lampshade
     3: a small rectangular free-reed instrument having a row of
        free reeds set back in air holes and played by blowing
        into the desired hole [syn: {harmonica}, {mouth organ}, {mouth
        harp}]

harp
     v 1: come back to; "Don't dwell on the past"; "She is always
          harping on the same old things" [syn: {dwell}]
     2: play the harp; "She harped the Saint-Saens beautifully"