magnum
n. countable C2 Proficiency US //ˈmæɡnəm// UK //mˈæɡnəm// mag·num
n. a very large bottle for wine or champagne. It is twice the size of a normal bottle and holds 1.5 litres.
n. a wine bottle with a capacity of 1.5 litres, equivalent to two standard 750ml bottles. Often associated with champagne or high-end still wines.
We ordered a magnum of champagne to celebrate the wedding.
The host brought out a magnum of red wine, knowing that a standard bottle wouldn't be enough for eight guests.
While a standard bottle is sufficient for a quiet dinner, the celebratory atmosphere of the gala demanded a magnum to ensure every guest could participate in the opening toast.
Usage
Often used in the phrase 'a magnum of [liquid]'.