Preemption or pre-emption may refer to:

Legal

* FDA preemption, legal theory in the United States that exempts product manufacturers from tort claims regarding Food and Drug Administration approved products *

Federal preemption In the law of the United States, federal preemption is the invalidation of a U.S. state law that conflicts with federal law. Constitutional basis According to the Supremacy Clause (Article VI, clause 2) of the United States Constitution, This ...

, displacement of U.S. state law by U.S. Federal law *

Pre-crime ''Pre-crime'' (or ''precrime'') is the idea that the occurrence of a crime can be anticipated before it happens. The term was coined by science fiction author Philip K. Dick, and is increasingly used in academic literature to describe and critici ...

, a criminal justice system approaches to crimes not yet committed *

Pre-emption (Dominion Land Survey) Preemption or pre-emption may refer to: Legal * FDA preemption, legal theory in the United States that exempts product manufacturers from tort claims regarding Food and Drug Administration approved products * Federal preemption, displacement of ...

, a purchase right given to settlers under the 1872

Dominion Lands Act The ''Dominion Lands Act'' (long title: ''An Act Respecting the Public Lands of the Dominion'') was an 1872 Canadian law that aimed to encourage the settlement of the Canadian Prairies and to help prevent the area being claimed by the United Sta ...

* Pre-emption rights, the right of existing shareholders in a company to buy shares offered for sale before they are offered to the public *

Preemption (land) Preemption was a term used in the nineteenth century to refer to a settler's right to purchase public land at a federally set minimum price; it was a right of first refusal. Usually this was conferred to male heads of households who developed the p ...

, a type of land transfer in the United States, as in the Preemption Act of 1841 *

Preemption Line The Preemption Line (also spelled Pre-Emption) divided the aboriginal lands of western New York State awarded to New York from those awarded to Commonwealth of Massachusetts by the Treaty of Hartford of 1786. It was defined as the meridian (north ...

, the line that divided the Indian lands of western New York State, that had been awarded to New York, from those that had been awarded to the Commonwealth of Massachusetts by the Treaty of Hartford of 1786 * State preemption, displacement of U.S. municipal law by state law

Other

Preempt Preempt (also spelled "pre-empt") is a bid in contract bridge whose primary objectives are (1) to thwart opponents' ability to bid to their best contract, with some safety, and (2) to fully describe one's hand to one's partner in a single bid. A ...

, a type of bid and a bidding tactic in contract bridge *

Preemption (computing) In computing, preemption is the act of temporarily interrupting an executing task, with the intention of resuming it at a later time. This interrupt is done by an external scheduler with no assistance or cooperation from the task. This preempt ...

, the interruption of a computer process without its cooperation in order to perform another task * Preemption (telecommunications), situation where one communication source is prioritised over another, in case of limited (radio) channel capacity * "Preemption", a form of broadcasting

blackout (broadcasting) In broadcasting, the term blackout refers to the non-airing of television or radio programming in a certain media market. It is particularly prevalent in the broadcasting of sports events, although other television or radio programs may be blac ...

Preemptive war A preemptive war is a war that is commenced in an attempt to repel or defeat a perceived imminent offensive or invasion, or to gain a strategic advantage in an impending (allegedly unavoidable) war ''shortly before'' that attack materializes. It ...

or preemptive strike *

Traffic signal preemption Traffic signal preemption (also called traffic signal prioritisation) is a system that allows the normal operation of traffic lights to be preempted. The most common use of these systems manipulates traffic signals in the path of an emergency vehi ...

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