arsenio-|ɑːˈsiːnɪəʊ|comb. form of next, as in arˈsenio-ˈsulphide, -ˈsulphuret, Chem., a compound of arsenious sulphide with a metallic sulphide; an arseno-sulphide. arˈsenio-ˈsiderite, Min.[σίδηρος iron], a fibrous mineral of yellowish-brown and somewhat golden colour, containing arsenic acid, sesquioxide of iron, and lime (Dana).