double up

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• verb transitive To double the quantity, amount or duration of something
• verb poker, by extension, intransitive To double one's amount of chips by winning an all-in pot.
• verb To bend, bend over; to fold; to stoop.
• verb intransitive To have a secondary use.
• verb baseball, transitive To get the second out in a double play, typically referring to getting an out by beating a runner back to a base (often by throwing) after a fly ball has been caught
• verb intransitive To employ double the usual resources for a particular purpose.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb stake winnings from one bet on a subsequent wager
• verb bend over or curl up, usually with laughter or pain
• verb share a room or a bed designed for only one person