/ Dictionary / Index S signal box: Meaning and Definition of Find definitions for: sig'nal box" Pronunciation: [key] — Brit. Brit. a railway signal tower. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. signal board signal corps 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