Triassic

American  

[trahy-as-ik] / traɪˈæs ɪk /

adjective

1. noting or pertaining to a period of the Mesozoic Era, occurring from 230 to 190 million years ago and characterized by the advent of dinosaurs and coniferous forests.

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noun

1. Also Trias the Triassic Period or System.

Triassic British  

/ traɪˈæsɪk /

adjective

1. of, denoting, or formed in the first period of the Mesozoic era that lasted for 42 million years and during which reptiles flourished

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noun

1. the Triassic period or rock system

Triassic Scientific  

/ trī-ăs′ĭk /

1. The earliest period of the Mesozoic Era, from about 245 to 208 million years ago. During the early part of the Triassic Period the supercontinent Pangaea was located along the equator; by the end of the Triassic it had started to split up. Land life diversified in the Triassic in response to the mass extinctions of the end of the Paleozoic. Conifers, cycads, marine reptiles, dinosaurs, and the earliest mammals first appeared.

2. See Chart at geologic time

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Other Word Forms

Derived Forms

• post-Triassic
  adjective

Etymology

Origin of Triassic

1835–45; Trias the three-part series of strata characterizing the period (< German < Greek triás; see triad) + -ic

Example Sentences

During the Triassic Period, many of the major animal groups we know today were only beginning to evolve.

From Science Daily • May 29, 2026

As the researchers note, the Triassic was an era full of evolutionary surprises.

From Science Daily • May 29, 2026

Arenaerpeton lived in freshwater environments within what is now the Sydney Basin during the Triassic period, around 240 million years ago.

From Science Daily • May 6, 2026

The species of crocodylomorph roamed Earth about 215 million years ago during the Triassic period and is believed to have been a fast-moving, land-dwelling predator resembling a "reptilian greyhound".

From BBC • Feb. 17, 2026

“They lived from the late Triassic to the Cretaceous period, though technically they’re not dinosaurs,” Kavita says in a know-it-all sort of way.

From "Dragons in a Bag" by Zetta Elliott