noun
Miocene epoch
Geological epoch from about 23 to 5.3 million years ago. Used in scientific and educational contexts.
中新世には、哺乳類がさらに多様化した。
During the Miocene epoch, mammals diversified further.
From 中 (middle) + 新 (new) + 世 (epoch), a calque of the English 'Miocene'.