/ Dictionary / Index I isotopic spin: Meaning and Definition of Find definitions for: i'sotop'ic spin' Pronunciation: [key] — Physics. Physics. a quantum number that is related to the number of different values of electric charge that a given kind of baryon or meson may have. Symbol: I&hasp; Also calledi Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. isotopic number isotopy Related Content Daily Word Quiz: pundit Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language