/ Dictionary / Index R ruling grade: Meaning and Definition of Find definitions for: rul'ing grade" Pronunciation: [key] — Railroads. Railroads. the steepest grade on a given stretch of track, which determines the maximum tonnage that can be hauled in a train having a given horsepower at a stated minimum speed. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. ruling elder rum Related Content Daily Word Quiz: perspicacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language