As a proper noun harp
is for a player of the harp.
As a noun scream is
a loud, emphatic, exclamation of extreme emotion, usually horror, fear, excitement et cetera can be the exclamation of a word, but is usually a sustained, high-pitched vowel sound, particularly /æ/ or /i/.
As a verb scream is
to cry out with a shrill voice; to utter a sudden, sharp outcry, or shrill, loud cry, as in fright or extreme pain; to shriek; to screech.