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

• 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

This discovery adds to the growing list of species known from the Late Triassic in this region.

From Science Daily • Mar. 21, 2026

Bodenham's discovery adds another piece to the growing diversity of animals living in this region during the Late Triassic before the Triassic–Jurassic mass extinction event caused by an increase in volcanic activity altering the climate.

From BBC • Feb. 17, 2026

Thrinaxodon belonged to a group called cynodonts, animals from the early Triassic period that show a mix of reptile and mammal traits.

From Science Daily • Jan. 19, 2026

In the Triassic period - between about 250 and 201 million years ago - the wall was a tidal flat, which later became part of the Alpine chain.

From BBC • Dec. 16, 2025

“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