aluminosilicate Syllabification: (a·lu·mi·no·sil·i·cate)Pronunciation: /əˌlo͞omənəˈsilikit/Definition of aluminosilicate noun Chemistry a silicate in which aluminum replaces some of the silicon, especially a rock-forming mineral such as a feldspar or a clay mineral. Origin: early 20th century: from alumino- (combining form of aluminum) + silicatealuminosilicate in other Oxford dictionaries Definition of aluminosilicate in the British & World English dictionary