noun

• (countable, uncountable) A sparkling white wine made from a blend of grapes, especially Chardonnay and pinot, produced in Champagne, France, by the méthode champenoise.
  "We suppose that this author has done his best to be satirical; and he may have thought that his subject would have inspired him with all that was smart and piquant: but the plain truth is that the promised champagne turns out to be vapid small beer."
• (countable, uncountable, informal) Any sparkling wine made by the méthode champenoise.
  "I’ve been saving an excellent Brazilian champagne for a special occasion."
• (countable, uncountable, informal) Any sparkling white wine.
• (countable) A glass of champagne.
  ""I'm not scared of needles, but I certainly don’t like them," she says. "I had a champagne en route to the clinic – maybe two – which I'd probably not recommended, but whatever works, right?[…]""

adj

• (heraldry) Alternative form of champaine.
  "A Point Dexter parted, A Point Champagne, A Point plain, A Point in Point, […]"

verb

• (transitive) To ply or treat with champagne.
  "And equally, the central matter of Henry's infidelities has no actual dramatisation, so that we never see him coming out of a stage door with a Follies girl on his arm, or champagning a debutante, let alone entering a boudoir."
• (intransitive) To drink champagne.
  "We clareted and champagned till two—then supped, and finished with a kind of regency punch composed of madeira, brandy, and green tea, no real water being admitted therein."