Miocene

American  

[mahy-uh-seen] / ˈmaɪ əˌsin /

adjective

1. noting or pertaining to an epoch of the Tertiary Period, occurring from 25 to 10 million years ago, when grazing mammals became widespread.

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noun

1. the Miocene Epoch or Series.

Miocene British  

/ ˈmaɪəˌsiːn /

adjective

1. of, denoting, or formed in the fourth epoch of the Tertiary period, between the Oligocene and Pliocene epochs, which lasted for 19 million years

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noun

1. this epoch or rock series

Miocene Scientific  

/ mī′ə-sēn′ /

1. The fourth epoch of the Tertiary Period, from about 24 to 5 million years ago. During this time the climate was warmer than it had been in the Oligocene, and kelp forests and grasslands first developed. With the isolation of Antarctica, a circumpolar ocean current was established in the southern Hemisphere, reducing the amount of mixing of cold polar water and warm equatorial water and causing a buildup of ice sheets in Antarctica. The African-Arabian plate became connected to Asia, closing the seaway which had previously separated Africa from Asia. Mammalian diversity was at its peak.

2. See Chart at geologic time

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Other Word Forms

• post-Miocene
  adjective

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Etymology

Origin of Miocene

First recorded in 1825–35; mio- (from Greek meíōn “less”) + -cene

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Example Sentences

See Examples For:

Miocene

"Our data indicate that the most significant collisional events between Central and South America occurred earlier than we previously thought, mainly during the Oligocene-middle Miocene," explain Piedrahita and Li.

From Science Daily ● Sep. 9, 2026

During the Miocene, a geological period that lasted for millions of years, a vast lake covered a large portion of the continent.

From Science Daily ● Aug. 19, 2026

Their results indicate that Masripithecus was more closely related to living apes than any Early Miocene species currently known from East Africa.

From Science Daily ● Jul. 24, 2026

During the Miocene, the area experienced warm and wet rainforest conditions.

From Science Daily ● Apr. 23, 2026

I told him I was studying hard because I wanted to become either a veterinarian or a geologist specializing in the Miocene period, when the mountains out west were formed.

From "The Glass Castle" by Jeannette Walls

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