collodion UK /kəˈləʊdiən/US /kəˈloʊdiən/ noun1 •A syrupy solution of nitrocellulose (pyroxylin) in alcohol and ether that evaporates on a surface to form a clear elastic film; used in surgical dressings, photographic plates and lacquer paints.The mysterious odour of collodion permeates these memories. — 1993 formscollodions