/ Dictionary / Index D D.L.O.: Meaning and Definition of Find definitions for: D.L.O. Pronunciation: [key] dead letter office. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. D. Litt. dlr. Related Content Daily Word Quiz: stellar Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language