tonality vs minor key

tonality and minor key both are nouns.

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

As nouns, minor key is a hyponym of tonality; that is, minor key is a word with a more specific, narrower meaning than tonality:

tonality: any of 24 major or minor diatonic scales that provide the tonal framework for a piece of music
minor key: a key based on the minor scale

Other hyponyms of tonality include major key, major mode, minor mode, home key, tonic key.

tonality (noun)	minor key (noun)
any of 24 major or minor diatonic scales that provide the tonal framework for a piece of music	a key based on the minor scale