keep something/someone at bay
keep something/someone at bayor
hold something/someone at bay
COMMON If you keep something or someone at bay or hold them at bay, you stop them from attacking you or harming you. By salting the meat, bacteria were kept at bay, preserving the meat for future use. Tooth decay can be held at bay by fluoride toothpaste and good dentistry. A dozen American soldiers held the crowd at bay until the helicopter lifted off. Note: When a hunted animal is at bay, it is trapped by the hounds (= hunting dogs) and forced to turn and face them to defend itself. However, if the animal is successfully defending itself in this position, you can say that it is holding the hounds at bay. This second use seems the most likely origin of the expression.