A Subatomic Particle With Virtually No Mass
This page is the CodyCross answer for the clue below from Mexico, Group 1373, Puzzle 5 (Pozole and Menudo).
Question is: A Subatomic Particle With Virtually No Mass
and the answer is: NEUTRINO
Word Meaning:
NEUTRINO — An elementary particle that is classified as a lepton, and has an extremely small but nonzero mass and no electric charge. It interacts with the surroundings only via the weak force or gravitation, making it very difficult to detect.
Definitions from Wiktionary.