minor mode vs minor key

minor mode and minor key both are nouns.

Word	Noun	Adjective	Verb	Adverb
minor mode	Yes	No	No	No
minor key	Yes	No	No	No

As nouns, minor mode and minor key are synonyms defined as:

minor mode (noun)	minor key (noun)
a key based on the minor scale	a key based on the minor scale