Definition of Eocene in English:



  • 1Relating to or denoting the second epoch of the Tertiary period, between the Palaeocene and Oligocene epochs.

    • ‘The La Meseta Formation is the best exposed and most fossiliferous rock unit of Eocene age in Antarctica.’
    • ‘It includes the Palaeocene, Eocene, and Oligocene epochs, spanning the time from the end of the Mesozoic to the beginning of the Neogene.’
    • ‘This age is notable because it is precisely the age of the boundary between the Paleocene and Eocene epochs.’
    • ‘Western Ecuador consists of a complex tectonic melange of oceanic terranes accreted to the continental margin from Late Cretaceous to Eocene time.’
    • ‘An early Cretaceous to late Eocene volcanic arc was located in the present-day Central Depression.’
    1. 1.1as noun the Eocene The Eocene epoch or the system of rocks deposited during it.

The Eocene epoch lasted from 56.5 to 35.4 million years ago. It was a time of rising temperatures, and there was an abundance of mammals, including the first horses, bats, and whales


Mid 19th century: from Greek ēōs ‘dawn’ + kainos ‘new’.