/pay"lee euh jeen'/ ; esp. Brit. /pal"ee-/ , Geol.
adj.
1. noting or pertaining to the earlier part of the Cenozoic Era, in the system adopted by some geologists, occurring from 65 to 25 million years ago and including the Oligocene, Eocene, and Paleocene epochs: corresponds to the earlier part of the Tertiary Period in the system generally used in the U.S. Cf. Neogene .
n.
2. the Paleogene Period or System.
[ 1880-85; Paläogen, equiv. to paläo- PALEO- + -gen ( genésthai to be born); cf. -GEN ]