fall-board vs fallboard

fall-board and fallboard both are nouns.

Word	Noun	Adjective	Verb	Adverb
fall-board	Yes	No	No	No
fallboard	Yes	No	No	No

As nouns, fall-board and fallboard are synonyms defined as:

fall-board and fallboard: the hinged protective covering that protects the keyboard of a piano when it is not being played

fall-board (noun)	fallboard (noun)
the hinged protective covering that protects the keyboard of a piano when it is not being played	the hinged protective covering that protects the keyboard of a piano when it is not being played