Definify.com
Webster 1913 Edition
Miocene
Mi′o-cene
(mī′ō̍-sēn)
, p
rop.
 Adj.
 [Gr. 
μείων 
less + καινόσ 
new, fresh, recent.] (Geol.) 
Of or pertaining to the middle division of the Tertiary. 
– Noun.
 The Miocene period. See 
 Chart 
of Geology
.