singleton vs unity

singleton and unity both are nouns.

Word	Noun	Adjective	Verb	Adverb
singleton	Yes	No	No	No
unity	Yes	No	No	No

As nouns, unity is a hypernym of singleton; that is, unity is a word with a broader meaning than singleton:

Other hypernyms of singleton include 1, ace, I, one, single.

singleton (noun)	unity (noun)
the playing card that is the only card in a suit held in a bridge hand as initially dealt	the quality of being united into one
a set containing a single member	the smallest whole number or a numeral representing this number
a single object (as distinguished from a pair)	an undivided or unbroken completeness or totality with nothing wanting