aneolithic

As an adjective aeneolithic

is describing that part of the neolithic period during which copper implements were in use alongside those of flint.

As a noun aneolithic is

the eneolithic, chalcolithic or copper age.

As a noun aneolithic

is the eneolithic, chalcolithic or copper age.

As an adjective Neolithic is

of or relating to the New Stone Age.

As a proper noun Neolithic is

the New Stone Age, from circa 8500 to 4500 BCE.