/ Dictionary / Index B block system: Meaning and Definition of Find definitions for: block' sys"tem Pronunciation: [key] — Railroads. Railroads. a series of consecutive blocks. Cf. block (def. 22). a system of blocks and block signals for controlling train movements. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. block signal block tin Related Content Daily Word Quiz: secular Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language