/ Dictionary / Index D derailment: Meaning and Definition of Find definitions for: de•rail•ment Pronunciation: (dē-rāl'munt), [key] — n. the act or process of derailing. See Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: derailment (Thesaurus) derailleur Derain Related Content Daily Word Quiz: diaphanous Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language