/ Dictionary / Index C Castlereagh: Meaning and Definition of Find definitions for: Cas•tle•reagh Pronunciation: (kas'ul-rā", kä'sul-), [key] (2nd Marquess of Londonderry), 1769–1822, British statesman. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. castle nut Castle Shannon Related Content Daily Word Quiz: abstain Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language