normalcy vs commonness

normalcy and commonness both are nouns.

Word	Noun	Adjective	Verb	Adverb
normalcy	Yes	No	No	No
commonness	Yes	No	No	No

As nouns, commonness is a hyponym of normalcy; that is, commonness is a word with a more specific, narrower meaning than normalcy:

normalcy: being within certain limits that define the range of normal functioning
commonness: the state of being that is commonly observed

Other hyponyms of normalcy include averageness, expectedness, typicality.

normalcy (noun)	commonness (noun)
expectedness as a consequence of being usual or regular or common	ordinariness as a consequence of being frequent and commonplace
being within certain limits that define the range of normal functioning	sharing of common attributes
	the quality of lacking taste and refinement
	the state of being that is commonly observed