/mag"neuhm/ , n.
1. a large wine bottle having a capacity of two ordinary bottles or 1.5 liters (1.6 quarts).
2. a magnum cartridge or firearm.
adj.
3. (of a cartridge) equipped with a larger charge than other cartridges of the same size.
4. (of a firearm) using such a cartridge.
5. Informal. unusually great in power or size: a magnum spotlight; a magnum dosage.
[ 1780-90; magnus large; in reference to firearms, orig. used as a trademark by the Smith and Wesson Co. ]