alpha and omega vs eternity

alpha and omega and eternity both are nouns.

Word	Noun	Adjective	Verb	Adverb
alpha and omega	Yes	No	No	No
eternity	Yes	No	No	No

As nouns, eternity is a hypernym of alpha and omega; that is, eternity is a word with a broader meaning than alpha and omega:

Other hypernyms of alpha and omega include infinity.

alpha and omega (noun)	eternity (noun)
the basic meaning of something; the crucial part	a state of eternal existence believed in some religions to characterize the afterlife
the first and last; signifies God's eternity	time without end
	a seemingly endless time interval (waiting)