Definition of "harp"

The Harpe. […] A harper with his wreſt maye tune the harpe wrong / Mys tunying of an Inſtrument ſhal hurt a true ſonge

1568, William Cornishe [i.e., William Cornysh], “In the Fleete Made by Me William Cornishe otherwise Called Nyshwhete Chapelman with the Most Famose and Noble Kyng Henry the VII. His Reygne the XIX. Yere the Moneth of July. A Treatise betwene Trouth, and Information.”, in John Skelton, edited by J[ohn] S[tow], Pithy Pleasaunt and Profitable Workes of Maister Skelton, Poete Laureate, Imprinted at London: In Fletestreate, neare vnto Saint Dunstones Churche by Thomas Marshe; republished as Pithy Pleasaunt and Profitable Workes of Maister Skelton, Poete Laureate to King Henry the VIIIth, London: Printed for C. Davis in Pater-noster Row, 1736, page 290

Contains charts and instructions for wiring. Shows sockets, wire, harps, glass chimneys and globes, shade holders, bases, finials, and hundreds of items necessary in the building of lamps.

1960, School Shop, volume 20, page 36

Both types of harp have a swiveling shade holder at the top. The threaded stud on the swivel accepts the finial.

1991, Kalton C. Lahue, ‎Cheryl Smith, Interior Lighting (page 104)

More likely, it was the prospect of meat. Curwen was by now craving a juicy roast – 'even seal chop' – and was always loosing off at tickleasses and harps.

2006, John Gimlette, Theatre of Fish: Travels Through Newfoundland and Labrador, page 225

Thou harped my fear aright.

c. 1606 (date written), William Shakespeare, “The Tragedie of Macbeth”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act IV, scene iv]