Meaning

noun from 58 million to 40 million years ago; presence of modern mammals

originFrom Ancient Greek ἠώς (ēṓs, “dawn”) + καινός (kainós, “new”) and refers to the "dawn" of modern ('new') fauna that appeared during the epoch. Coined by English polymath William Whewell in 1831 for Charles Lyell, who introduced it in 1833 in his book Principles of Geology. By surface analysis, eo- + -cene.

Etymology from Wiktionary, CC BY-SA 3.0