pion

Any of the three least massive mesons, having a positive, neutral, or negative electric charge. The charged pions have a mass 273 times that of an electron and a mean lifetime of 2.6 × 10⁻⁸ second, and the neutral pion has a mass 264 times that of an electron and a mean lifetime of 8.4 × 10⁻¹⁷ second.

Any of three semistable mesons, having positive, negative or neutral charge, composed of up and down quarks/antiquarks.

a meson involved in holding the nucleus together; produced as the result of high-energy particle collision