aged vs age bracket

aged and age bracket both are nouns.

Word	Noun	Adjective	Verb	Adverb
aged	Yes	Yes	No	No
age bracket	Yes	No	No	No

As nouns, age bracket is a hypernym of aged; that is, age bracket is a word with a broader meaning than aged:

Other hypernyms of aged include age group, cohort.

aged (noun)	age bracket (noun)
people who are old collectively	a group of people having approximately the same age

aged (adjective)	age bracket (adjective)
(used of tobacco) aging as a preservative process
of wines, fruit, cheeses; having reached a desired or final condition; (`aged' pronounced as one syllable)
at an advanced stage of erosion (pronounced as one syllable)
advanced in years; (`aged' is pronounced as two syllables)
having attained a specific age; (`aged' is pronounced as one syllable)