Proper noun
Copper Age (uncountable)
(archaeology) A short or theoretical prehistoric period between the Neolithic and Bronze Age.
After several years, a number of complaints appeared in the literature that "Eneolithic" seemed to the untrained eye to be produced from e-neolithic, "outside the Neolithic," clearly not a definitive characterization of the Copper Age. Source: Internet
He does not mention the adjective of aes, which is aēneus, nor is he interested in formulating New Latin words for the Copper Age, which is good enough for him and many English authors from then on. Source: Internet
Hippos, which had been occupied for thousands of years - shards have been found from the Copper Age, around 5,000 years ago - was destroyed by an earthquake in 749. By that time, most of the churches were no longer in use. Source: Internet