/ Dictionary / Index M mailing tube: Meaning and Definition of Find definitions for: mail'ing tube" Pronunciation: [key] an elongated cylinder of cardboard, used for mailing rolled-up papers, magazines, etc. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. mailing machine maill Related Content Daily Word Quiz: philtrum Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language