Jew's harp

noun1

1. •
   A musical instrument consisting of a thin flexible reed mounted in a stiff crescent frame. The narrow end of the frame is held between the teeth and the reed is plucked to produce a note of constant pitch. Melodies and overtones are created by changing the shape of the oral cavity.

   • The lad, his son, had obtained a Jew's-harp, and learned to play upon it the profane airs of "Yankee Doodle," "Hail Columbia," "St. Patrick's Day," and "Auld Lang Syne." — 1850