From The Collaborative International Dictionary of English v.0.48:
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. [1913 Webster]
Thou 'st harped my fear aright. --Shak. [1913 Webster]
From The Collaborative International Dictionary of English v.0.48:
Harp \Harp\ (h[aum]rp), 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. [1913 Webster]
2. (Astron.) A constellation; Lyra, or the Lyre. [1913 Webster]
3. A grain sieve. [Scot.] [1913 Webster]
Aeolian harp. See under Aeolian. [1913 Webster]
Harp seal (Zool.), 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; their fur is white, and they are killed and skinned to harvest the fur.
Harp shell (Zool.), a beautiful marine gastropod shell of the genus Harpa, of several species, found in tropical seas. See Harpa. [1913 Webster]
From The Collaborative International Dictionary of English v.0.48:
Harp \Harp\, v. i. [imp. & p. p. Harped (h[aum]rpt) p. pr. & vb. n. Harping.] [AS. hearpian. See Harp, n.] 1. To play on the harp. [1913 Webster]
I heard the voice of harpers, harping with their harps. --Rev. xiv. 2. [1913 Webster]
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. [1913 Webster]
Harping on what I am, Not what he knew I was. --Shak. [1913 Webster]
To harp on one string, to dwell upon one subject with disagreeable or wearisome persistence. [Colloq.] [1913 Webster]