/ Dictionary / Index E extended real number system: Meaning and Definition of Find definitions for: extend'ed real' num'ber sys"tem Pronunciation: [key] — Math. Math. the set of all real numbers with the points plus infinity and minus infinity added. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. extended play extended term insurance Related Content Daily Word Quiz: cygnet Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language