From Longman Dictionary of Contemporary Englishzitherzith‧er /ˈzɪðə $ -ər/ noun [countable] APMa musical instrument from Eastern Europe that consists of a flat box with strings stretched across it. You play it by pulling the strings with your fingers or a plectrum (=small piece of plastic, metal etc).
Examples from the Corpus
zither• Both zither and dance music are played once a week.• Once a week there is a gala buffet with zither music.Origin zither (1800-1900) German Greek kithara type of stringed instrument 