noun: Initialism of Professional Bull Riders, a sport, circuit, and company for bull riding
noun: Initialism of Pabst Blue Ribbon, a brand of beer
noun: Initialism of patrol boat, rigid, a type of river patrol boat used by the US Navy during the Vietnam War [A relatively small naval vessel designed for coastal defence.]
noun: Initialism of plastic baton round, a type of non-lethal projectile more commonly known as the plastic bullet [A non-lethal projectile made of aluminium carcase and plastic head, designed to be fired from a specialized gun, for riot control.]
noun: (nuclear physics, engineering) Initialism of pebble-bed reactor. [A form of nuclear reactor using spherical fuel elements which are individually processed and fed through the reactor.]
noun: (computing) Initialism of policy-based routing.
noun: (ecology) Initialism of potential biological removal.