a. [ Written also pleiocene. ] [ Gr. &unr_; more + &unr_; new, recent. ] (Geol.) Of, pertaining to, or characterizing, the most recent division of the Tertiary age. [ 1913 Webster ]
a. (Geol.) [ Pref. post- + pliocene. ] Of or pertaining to the period immediately following the Pliocene; Pleistocene. Also used as a noun. See Quaternary. [ 1913 Webster ]