mag·num 
(măgnəm)
(măgnəm)adj.
1. Of or relating to a cartridge containing a larger explosive charge than other cartridges of the same size.
2. Designed to shoot magnum cartridges.
n.
1. A magnum cartridge or firearm.
2.
a. A bottle, holding about two fifths of a gallon (1.5 liters), for wine or liquor.
b. The amount of liquid that this bottle can hold.
[From Latin, neuter of magnus, great; see meg- in the Appendix of Indo-European roots.]