(oil industry) A device that sits at the surface interface of an oil well and prevents a blowout from occurring by closing the orifice, allowing material to flow from the oil reservoir out through the shaft.

plural of blowout preventer

Maintenance done to keep something in working order rather than to repair damage that has already happened.

War started by one of the parties without having received any attack from the other party. This type of war is initiated by states unable to use diplomacy

Work done by the coastguard to prevent smuggling.

plural of preventive service

(medicine) medicine given to prevent illness, rather than treat it.

(team sports) Any defense intended to prevent rapid scoring by the offense, at the expense of allowing relatively easy, slower scoring.

plural of preventive war

It is better to prevent the creation of a problem than to have to deal with it afterwards.