1) Early geologic period 2) Geologic-time division 3) Geological period 4) Part of the Cenozoic 5) Part of the Tertiary Period 6) Tertiary period 
• (a.) More recent than the Eocene, that is, including both the Miocene and Pliocene divisions of the Tertiary. • (a.) More recent than the Eocene, that is, including both the Miocene and Pliocene divisions of the Tertiary.
Ne'o·cene adjective [ Neo- + Greek ... new.] (Geol.) More recent than the Eocene, that is, including both the Miocene and Pliocene divisions of the Tertiary. 
Neocene More recent than the Eocene, that is, including both the Miocene and Pliocene divisions of the Tertiary.