/ Dictionary / Index B Buenos Aires: Meaning and Definition of Find definitions for: Bue•nos Ai•res Pronunciation: (bwā'nus īr'iz, bō'nus Sp. bwe'nôs ī'res), [key] a seaport in and the capital of Argentina, in the E part, on the Río de la Plata. 9,927,404. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. bueno* buenos días* Related Content Daily Word Quiz: hedonist Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language