age vs voting age

age and voting age both are nouns.

Word	Noun	Adjective	Verb	Adverb
age	Yes	No	Yes	No
voting age	Yes	No	No	No

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

age: a time of life (usually defined in years) at which some particular qualification or power arises
voting age: the age at which a person is old enough to vote in public elections

Other hyponyms of age include age of consent, legal age, majority, minority, nonage, drinking age.

age (noun)	voting age (noun)
how long something has existed	the age at which a person is old enough to vote in public elections
a time of life (usually defined in years) at which some particular qualification or power arises
a late time of life
an era of history having some distinctive feature
a prolonged period of time