Although the doctors had been able to 'keep her illness at bay' [=to prevent her illness from becoming worse] for a few months, the disease soon began to spread again.
Armed with a gun, he 'held the police at bay' [=he did not allow the police to arrest him] for 10 hours.
The soldiers 'kept the attackers at bay'. [=they did not allow the attackers to come closer]
(..) and a right, huh? -Thanks for the directions, okay? -Yeah. And remember, kid... Buzz! It's safer in the cockpit than the cargo bay. What an idiot. Next shuttle lift-off is scheduled for T-minus minutes and counting. You are clear to enter. Welcome to Pizza Planet. (..)1995 Toy Story