psaltery
noun
psal·tery ˈsäl-t(ə-)rē 
ˈsȯl-
variants or less commonly psaltry
plural psalteries also psaltries
: an ancient musical instrument resembling the zither
Word History
Etymology
Middle English psalterie, from Anglo-French, from Latin psalterium, from Greek psaltērion, from psallein to play on a stringed instrument
First Known Use
14th century, in the meaning defined above