something that is twice as big, as much etc as usual or as something else:
twice the size[uncountable and countable]
Scotch and water, please - make it a double.
'They offered me £10,000.' 'I'll give you double.'
a room for two people in a hotel [↪ single]:
A double costs $95 a night.
a game played between two pairs of players, especially in tennis [↪ singles]: ➔ mixed doubles
the men's doubles
a hit in baseball which allows the batter to reach second base:
Walker led the inning with a double.
someone who looks very like someone else:
She's her mother's double.
an actor who takes the place of a more famous actor in a film, especially because the acting involves doing something dangerous:
I think they used a double in the shower scene.
7 British English, on the double American English informal
very quickly and without any delay:
He was told to get back to Washington on the double.
8 British English double or nothing American EnglishDGG
a situation in a game when you must do something that could either win you twice as much money or make you lose it all