[ sʌɪ'ljʊərɪən , sɪ- ]
■ adjective Geology relating to or denoting the third period of the Palaeozoic era (between the Ordovician and Devonian periods, about 439–409 million years ago), a time when land plants and the first true fish appeared.
Origin
C18: from Silures , the L. name of a people of ancient SE Wales + -ian .