/ Dictionary / Index O Oil Rivers: Meaning and Definition of Find definitions for: Oil' Riv'ers Pronunciation: [key] a region in W Africa, comprising the vast Niger River delta: formerly a British protectorate; now a part of Nigeria. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. oil-plant oil sand Related Content Daily Word Quiz: loathe Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language