/ Dictionary / Index S submachine gun: Meaning and Definition of Find definitions for: sub•ma•chine' gun" Pronunciation: (sub"mu-shēn'), [key] a lightweight automatic or semiautomatic gun, fired from the shoulder or hip. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. subluxation submandibular gland Related Content Daily Word Quiz: endear Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language