pion rocket

Etymology
From the type of exhaust expelled by the rocket, being composed of &pi; subatomic particles (&pi; mesons, aka pions).

Noun

 * 1) A theoretical type of antimatter rocket which uses proton-antiproton fuel, and magnetic rocket funnels to direct the &pi;-on exhaust. The pi meson particles are created by the matter-antimatter annihilation of protons and antiprotons.