/ Dictionary / Index N Northumberland: Meaning and Definition of Find definitions for: North•um•ber•land Pronunciation: (nôr-thum'bur-lund), [key] — n. a county in NE England. 286,700; 1943 sq. mi. (5030 sq. km). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: northumberland (Thesaurus) North Tonawanda Northumberland Strait Related Content Daily Word Quiz: eureka Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language