/ Dictionary / Index S subatom: Meaning and Definition of Find definitions for: sub•at•om Pronunciation: (sub-at'um), [key] — n. Chem. any component of an atom. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. subatmospheric subatomic Related Content Daily Word Quiz: neologism Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language