I. harp 1 /hɑːp $ hɑːrp/ BrE AmE noun [countable]
[ Language: Old English ; Origin: hearpe ]
a 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]
II. harp 2 BrE AmE verb
harp on about something British English , harp on something American English phrasal verb informal
to talk about something continuously, especially in a way that is annoying or boring:
My grandfather harps on about the war all the time.