/ Dictionary / Index B boundary rider: Meaning and Definition of Find definitions for: bound'ary rid"er Pronunciation: [key] — n. Australian. a ranch hand who patrols the boundary of a sheep or cattle station in order to watch the stock, repair fences, etc. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. boundary line boundary value problem Related Content Daily Word Quiz: blanch Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language