/ Dictionary / Index M megastructure: Meaning and Definition of Find definitions for: meg•a•struc•ture Pronunciation: (meg'u-struk"chur), [key] — n. a very large, usually high-rise building or a complex of such buildings used for many purposes, as for apartments, offices, stores, theaters, and athletic facilities. a very large, complex organization. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. megass megathere Related Content Daily Word Quiz: perspicacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language