/ Dictionary / Index L long tom: Meaning and Definition of Find definitions for: long' tom' Pronunciation: [key] — (usually caps.) a towed 155mm field cannon produced by the U.S. throughout World War II. a long, heavy cannon formerly carried by small naval vessels. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. longtime long ton Related Content Daily Word Quiz: frugal Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language