/ Dictionary / Index N National Academy of Sciences: Meaning and Definition of Find definitions for: Na'tional Acad'emy of Sci'ences Pronunciation: [key] a private organization, created by an act of Congress (1863), that furthers science and advises the U.S. government on scientific and technical issues. Abbr.: N.A.S., NAS Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. national National Aeronautics and Space Administration Related Content Daily Word Quiz: crutiny Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language