/ Dictionary / Index S signal board: Meaning and Definition of Find definitions for: sig'nal board" Pronunciation: [key] a board for displaying electrically transmitted signals and indicating their source. Cf. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. signal signal box 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