/ Dictionary / Index S substruction: Meaning and Definition of Find definitions for: sub•struc•tion Pronunciation: (sub-struk'shun), [key] — n. a foundation or substructure. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. substratum substructure 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