From Longman Dictionary of Contemporary Englishharpharp1 /hɑːp $ hɑːrp/ noun [countable] 
APMa large musical instrument with strings that are stretched across a vertical frame with three corners, and that you play with your fingers —harpist noun [countable]
APMa large musical instrument with strings that are stretched across a vertical frame with three corners, and that you play with your fingers —harpist noun [countable]Examples from the Corpus
harp• Power, a New Zealander, plays the blues harp and the chromatic harmonica.• The third time, Jack stole a golden harp and was almost caught.• When he married her, she was a reserved, very plain girl who played the harp in a provincial symphony orchestra.• Perhaps the biggest thing going was the harp played by JoAnn Turovsky, sounding positively, well, huge.• Remi was going to ny down in a stratosphere liner with this harp under his arm and make us all rich.harpharp2 verb → harp on about something→ See Verb tableExamples from the Corpus
harp• The speech therapist tells them, in effect, to calm down and stop harping on it and it will go away.• Karl Maclaren thinks the two are harping on one side of the issue too strongly.• Mr. Lilley Confidence will not be instilled by harping solely on the negatives.Origin harp1 Old English hearpe 