8 letters · 10 points in Scrabble
noun an elementary particle responsible for the forces in the atomic nucleus; a hadron with a baryon number of 0
originFrom meso- + -tron. Coined by American physicists Carl Anderson and Seth Neddermeyer in 1938 in a letter to Nature titled "Mesotron (Intermediate Particle) as a Name for the New Particles of Intermediate Mass".
Etymology from Wiktionary, CC BY-SA 3.0