singleness vs concentration

singleness and concentration both are nouns.

Word	Noun	Adjective	Verb	Adverb
singleness	Yes	No	No	No
concentration	Yes	No	No	No

As nouns, concentration is a hypernym of singleness; that is, concentration is a word with a broader meaning than singleness:

Other hypernyms of singleness include assiduity, assiduousness.

singleness (noun)	concentration (noun)
the quality of concentrating on one central objective	strengthening the concentration (as of a solute in a mixture) by removing diluting material
without hypocrisy	bringing together military forces
	great and constant diligence and attention
	the strength of a solution; number of molecules of a substance in a given volume
	the spatial property of being crowded together
	complete attention; intense mental effort
	increase in density