In the law of the United States, federal preemption is the invalidation of a U.S. state law that conflicts with federal law.

(also called traffic signal prioritisation) a system that allows an operator to override the normal operation of traffic lights.

In computer operating system design, kernel preemption is a property possessed by some kernels, in which the CPU can be interrupted in the middle of executing kernel code and assigned other tasks (from which it later returns to finish its kernel tasks).