pianoforte vs forte-piano

pianoforte and forte-piano both are nouns.

Word	Noun	Adjective	Verb	Adverb
pianoforte	Yes	No	No	No
forte-piano	Yes	No	No	No

As nouns, pianoforte and forte-piano are synonyms defined as:

pianoforte and forte-piano: a keyboard instrument that is played by depressing keys that cause hammers to strike tuned strings and produce sounds

Other synonyms of pianoforte include piano.

pianoforte (noun)	forte-piano (noun)
a keyboard instrument that is played by depressing keys that cause hammers to strike tuned strings and produce sounds	a keyboard instrument that is played by depressing keys that cause hammers to strike tuned strings and produce sounds