[ome.ga] n [ME, fr. MF, fr. Gk o mega, lit., large o] (15c) 1: the 24th and last letter of the Greek alphabet
2: last, ending 3 a: a negatively charged elementary particle that has a mass 3270 times the mass of an electron--called also omega minus b: a very short-lived unstable meson with mass 1532 times the mass of an electron--called also omega meson