Pronunciation: (bing'gō), [key]
—n. (sometimes cap.)
a form of lotto in which balls or slips, each with a number and one of the letters B, I, N, G, or O, are drawn at random and players cover the corresponding numbers printed on their cards, the winner being the first to cover five numbers in any row or diagonal or, sometimes, all numbers on the card.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.