▪ I.gaine|geɪn|[Fr., = sheath.]A metal tube attached to a fuse (seequots.).1918Nature 14 Nov. 218/1 The gaine is a metal tube screwed to the fuse, which enters a cavity in the filling and makes good contact with it.1932Lloyd George War Mem. II. xix. 592 A gaine..is a tube filled with explosive, attached under the nose-cap of a high-explosive shell... Its purpose is to ensure that the detonation of the fuse in the nose-cap shall effectively detonate the contents of the shell.▪ II.gaine, gaine-obs. forms of gain, gain-.