pion rocket

== English == === Etymology === From the type of exhaust expelled by the rocket, being composed of π subatomic particles (π mesons, aka pions). === Noun === pion rocket (plural pion rockets) A theoretical type of antimatter rocket which uses proton-antiproton fuel, and magnetic rocket funnels to direct the π-on exhaust. The pi meson particles are created by the matter-antimatter annihilation of protons and antiprotons.