car·tridge 
(kärtrĭj)
(kärtrĭj)n.
1.
a. A cylindrical, usually metal casing containing the primer and charge of ammunition for firearms.
b. Such a casing fitted with a bullet.
c. A similar piece of ammunition, such as a shotgun shell.
2. A case filled with high explosives, used in blasting.
3. A small modular unit designed to be inserted into a larger piece of equipment: an ink cartridge; a disposable cartridge of caulking compound.
4. A removable case containing the stylus and electric conversion circuitry in a phonograph pickup.
5.
a. A case containing magnetic tape in a reel; a cassette.
b. A case containing a ribbon in a spool, for use in printers and electric typewriters.
6. A lightproof case with photographic film that can be loaded directly into a camera.
[Alteration of earlier cartage, alteration of French cartouche, from Italian cartuccio, variant of cartoccio, roll of paper; see CARTOUCHE.]