n. Guncotton or a similar substance obtained by immersing vegetable fiber in nitric or nitrosulphuric acid, and then suffering it to dry. Such substances are nitro-derivatives of cellulose. Also pyroxyle.n. This term is now usually applied to the less highly nitrated product of the interaction of cellulose and nitric acid, soluble in a mixture of ether and alcohol, not to the more highly nitrated insoluble gun-cotton used as an explosive.