The phrase "a flagon of" is correct and usable in written English.
It can be used when referring to a large container, typically used for holding liquids like wine or beer, often in a historical or literary context.
Example: "The old tavern served its patrons a flagon of ale, filling the room with laughter and cheer."
Alternatives: "a jug of" or "a vessel of".
Single-note riffs, made of notes as fat and furrowed as truck tires, get pushed through old amps and a flagon of echo.
A remarkable insight into a lost world of magic and myth, best read with a flagon of golden mead – Odin and Snorri's favourite drink.
"Suppress prostitution, and capricious lusts will overthrow society," remarked St Augustine, eyeing a flagon of mead, and somewhat surprising the merry company with his fifth-century mixed morality.
Or there's cider where a flagon of scrumpy in September is the rugged equivalent of a jug of Pimms in June.
Beside him were a pound of sugar, a cup of coffee beans, a Granny Smith, and a flagon of fifty-five-proof grappa.
One 20th-century student reputedly demanded a flagon of claret during his exams, having discovered an ancient rule in the University Statute Book entitling him to.
Raise some kind of a flagon to Finnish bands like Turisas, the inventors of Battle Metal, or the wonderful, troll-obsessed folk-metal band Korpiklaani, who look and sound like they think rock was invented by Henry VIII after too much mead.
"This book has a slight pinch of comedy, a teaspoon of mystery and a whole flagon of brilliance", he wrote.
DRINKS Bottle service is encouraged (starting with a $250 flagon of Absolut).
We'd place a couple of sandwiches and a four-litre flagon of orange juice on top.
Of course, no trip to the Wizarding World of Harry Potter would be complete without a flagon (or three, in my case) of the butterscotchy/cream soda drink described by J.K. Rowling in her books, and brought to life at the Universal theme parks.
