/ Dictionary / Index F fermion: Meaning and Definition of Find definitions for: fer•mi•on Pronunciation: (fûr'mē-on"), [key] — n. Physics. any particle that obeys the exclusion principle and Fermi-Dirac statistics; fermions have spins that are half an odd integer: , , , . … Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: fermion (Thesaurus) Fermi-Dirac statistics fermium Related Content Daily Word Quiz: soporific Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language