siliceous si·li·ceous UK/sɪˈlɪ.ʃəs/ uncommon adjective 1. relating to or containing or resembling silica “gritrock is siliceous sandstone” Synonymssilicious Related words Pertaining to silica WordNet 2.1 (Princeton University). Wiktionary (CC BY-SA). WordNet 2.1 Copyright Princeton University. All rights reserved.
