In American and Canadian English, timeout is one word in sports-related contexts, where it means an official pause in the action. Timeouts is its plural. In all other uses, time out is a two-word noun phrase.
In British English, meanwhile, the one-word timeout is considered incorrect. Time out is preferred, even in sports.
Timeout (North America)
The Mavericks called a timeout and when Terry got to the bench, Barea was yelling at him. [Dallas Morning News]
Chris Wilcox appeared to receive most of his wrath during the timeout. [Globe and Mail]
Instead of calling an expected timeout to set up a play, Montclair Kimberley coach Paul Edwards allowed his kids to see it through without intervention. [The Star-Ledger]
Time out (North America)
He’d taken time out of a recruiting trip to Houston to stop by her office. [Houston Chronicle]
Think of the difficulty involved in catching a giant tarpon on light tackle your first time out. [Miami Herald]
This time out, he splits the difference and, consequently, gives the middle of the road an interesting sheen. [Globe and Mail]