Definition of Silurian in US English:



  • 1Relating to or denoting the third period of the Paleozoic era, between the Ordovician and Devonian periods.

    The Silurian lasted from about 439 million to 409 million years ago. The first true fish and land plants appeared during the period, and the end of the period is marked by the climax of the Caledonian orogeny

    • ‘Conventionally, the Cambrian, Ordovician, and Silurian systems constitute the Lower Palaeozoic and the Devonian, Carboniferous, and Permian comprise the Upper Palaeozoic.’
    • ‘These are overlain by low-grade metamorphosed sediments and volcanics of Ordovician and Silurian age.’
    • ‘Another hiatus occurs between the Kap Holbek Formation and the overlying middle Lower Ordovician - Silurian carbonate and elastic rocks.’
    • ‘The so-called ophiolitic relics at the Moldanubian-Brunovistulian boundary show Early Ordovician to Silurian crystallization ages.’
    • ‘Studies of acritarchs and chitinozoans suggest Ordovician to Silurian ages.’
    1. 1.1as noun the Silurian The Silurian period or the system of rocks deposited during it.


Early 18th century: from Latin Silures (denoting a people of ancient SE Wales) + -ian.