cither vs cithern

cither and cithern both are nouns.

Word	Noun	Adjective	Verb	Adverb
cither	Yes	No	No	No
cithern	Yes	No	No	No

As nouns, cither and cithern are synonyms defined as:

cither and cithern: a 16th century musical instrument resembling a guitar with a pear-shaped soundbox and wire strings

Other synonyms of cither include citole, cittern, gittern.

cither (noun)	cithern (noun)
a musical stringed instrument with strings stretched over a flat sounding board; it is laid flat and played with a plectrum and with fingers	a 16th century musical instrument resembling a guitar with a pear-shaped soundbox and wire strings
a 16th century musical instrument resembling a guitar with a pear-shaped soundbox and wire strings