[ si-loo r-ee-uh n, sahy- ]
/ sɪˈlʊər i ən, saɪ- /


of or relating to the Silures or their country.
Geology. noting or pertaining to a period of the Paleozoic Era, occurring from 425 to 405 million years ago, notable for the advent of air-breathing animals and terrestrial plants.


Geology. the Silurian Period or System of rocks.

Origin of Silurian

First recorded in 1700–10; Silur(es) + -ian


post-Si·lu·ri·an, adjectivepre-Si·lu·ri·an, adjective, noun Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

Examples from the Web for silurian

British Dictionary definitions for silurian

/ (saɪˈlʊərɪən) /


of, denoting, or formed in the third period of the Palaeozoic era, between the Ordovician and Devonian periods, which lasted for 25 million years, during which fishes first appeared
of or relating to the Silures


the Silurian the Silurian period or rock system
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for silurian

[ sĭ-lurē-ən ]

The third period of the Paleozoic Era, from about 438 to 408 million years ago. During this time glaciers that formed during the late Ordovician melted, causing sea levels to rise. The first coral reefs, fish with jaws, and freshwater fish appeared, and jawless fish continued to spread rapidly. The first vascular plants also appeared, as did land invertebrates including relatives of spiders and centipedes. See Chart at geologic time.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.