adj.
Pronunciation: ' ä-li-g ō - ˌ s ē n, ' ō -; ə - ' li-g ə -
Function: adjective
Etymology: International Scientific Vocabulary
Date: circa 1859
: of, relating to, or being an epoch of the Tertiary between the Eocene and Miocene or the corresponding series of rocks ― see GEOLOGIC TIME table
– Oligocene noun