/ Dictionary / Index B block line: Meaning and Definition of Find definitions for: block' line" Pronunciation: [key] a rope or chain running through the blocks of a tackle. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. block letter block mast Related Content Daily Word Quiz: paradox Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language